Cartridge for a liquid-cooled plasma arc torch

ABSTRACT

A torch head for a liquid-cooled plasma arc torch is provided. The torch head includes a torch body and a torch insulator, coupled to the torch body, having a substantially non-conductive insulator body. The torch insulator includes (i) a first liquid coolant channel, disposed within the insulator body, configured to conduct a fluid flow from the torch head into a consumable cartridge along a first preexisting flow path, (ii) a first liquid return channel, disposed within the insulator body, configured to return at least a portion of the fluid flow from the cartridge to the torch head along the first preexisting flow path, and (iii) a gas channel, disposed within the insulator body, configured to conduct a first gas flow from the torch head to the cartridge along a second preexisting flow path. The first and second preexisting flow paths are fluidly isolated from each other.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 62/200,913, filed Aug. 4, 2015, the entirecontent of which is owned by the assignee of the instant application andincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention generally relates to cartridges for aliquid-cooled plasma arc torch, and more particularly, to one or morereplaceable, low-cost cartridges having integrated components.

BACKGROUND

Thermal processing torches, such as plasma arc torches, are widely usedfor high temperature processing (e.g., heating, cutting, gouging andmarking) of materials. A plasma arc torch generally includes a torchhead, an electrode mounted within the torch head, an emissive insertdisposed within a bore of the electrode, a nozzle with a central exitorifice mounted within the torch head, a shield, electrical connections,passages for cooling, passages for arc control fluids (e.g., plasma gas)and a power supply. A swirl ring can be used to control fluid flowpatterns in the plasma chamber formed between the electrode and thenozzle. In some torches, a retaining cap is used to maintain the nozzleand/or swirl ring in the plasma arc torch. In operation, the torchproduces a plasma arc, which is a constricted jet of an ionized gas withhigh temperature and sufficient momentum to assist with removal ofmolten metal. Gases used in the torch can be non-reactive (e.g., argonor nitrogen), or reactive (e.g., oxygen or air).

Existing plasma cutting systems include a large array of separateconsumables available for use with different currents and/or operatingmodes that are repeatedly assembled and disassembled in the field by auser to perform thermal processing operations. The large number ofconsumable options requires large part counts and inventories for users,and can confuse users and increase the possibility of installingincorrect consumables. The large number of consumable options can alsocause lengthy torch setup time(s) and make it difficult to transitionamong cutting processes that require different arrangements ofconsumables in the torch that is often performed in the field onecomponent at a time. For example, before a cutting operation, selectingand installing the correct set of consumables for a particular cuttingtask can be burdensome and time-consuming. Furthermore, selection,assembly, and installation of these components in the field can causealignment issues or compatibility issues when old components are usedwith new components. During torch operation, existing consumables canexperience performance issues such as failing to maintain properconsumable alignment and spacing. Furthermore, current consumablesinclude substantial amounts of expensive materials (e.g., Vespel™) andoften require a relatively complex manufacturing process, which leads tosignificant manufacturing costs and inhibits their widespreadcommercialization, production and adoption. What is needed is a new andimproved consumable platform for liquid-cooled plasma arc torches thatdecreases manufacturing costs and time, decreases part count, increasessystem performance (e.g., component alignment, cut quality, consumablelife, variability/versatility, etc.), and eases installation and use ofconsumables by end users.

SUMMARY

The present invention provides one or more integrated, cost-effectivecartridge designs for a liquid-cooled plasma arc torch. Generally,because a cartridge includes a suite of two or more consumablecomponents, it provides ease of use and shortens the time forinstallation into a plasma arc torch in comparison toinstalling/replacing each consumable component individually. Using aconsumable cartridge also reduces the possibility of an operator puttingin the wrong consumable parts, contaminating the parts duringinstallation and/or placing a weak or bad part back onto the torch byaccident. These advantages eliminate the need for experienced operatorsto operate the resulting liquid-cooled plasma arc torches. In addition,the use of a cartridge in a liquid-cooled torch improves componentalignment, cut consistency and cut quality experience. Further, usingconsumable cartridges enhance suppliers' experience as fewer consumableparts need to be inventoried and stocked. In some cases, a supplier canbuy back used cartridges and recycle components for other uses. However,manufacturing and material costs can prohibit the widespreadcommercialization and production of cartridges. The present inventionsolves this problem by providing one or more cost effective cartridgedesigns that facilitate cartridge commercialization and production andimprove their installation.

In one aspect, the present invention features a consumable cartridgeframe for a liquid-cooled plasma arc torch, the consumable cartridgeframe includes an insulator body configured to be disposed between atorch head and a cartridge tip, a first cooling channel, disposed in thebody, configured to conduct a first fluid flow received from the torchhead to contact a component of the cartridge tip connected to thecartridge frame, and a first return channel, disposed in the body,configured to conduct at least a portion of the first fluid flow fromthe component to the torch head. The first cooling channel and the firstreturn channel are non-concentric in relation to a central longitudinalaxis of the body.

In some embodiments, the consumable cartridge frame further includes atorch engagement feature configured to radially secure the cartridge tipto the torch head in a predetermined orientation. The first coolingchannel can be configured to substantially align with a correspondingfirst cooling channel of the torch head when the cartridge tip isradially secured to the torch head via the torch engagement feature. Thefirst liquid cooling channel can be adapted to conduct a cooling liquidfrom the torch head into the cartridge tip. The first return channel canbe configured to substantially align with a corresponding first returnchannel of the torch head when the cartridge tip is radially secured tothe torch head via the torch engagement feature. The first returnchannel can be adapted to return the cooling liquid from the cartridgetip into the torch head.

In some embodiments, the consumable cartridge frame further includes acentral channel disposed in the insulator body and concentric withrespect to the central longitudinal axis of the insulator body, thecentral channel configured to perform at least one of (i) conduct thefirst fluid flow from the torch head to an electrode or (ii) pass anelectrical current from the torch head to the electrode. The consumablecartridge frame can further include a second cooling channel, disposedin the insulator body, configured to conduct at least a portion of thefirst fluid flow received from the torch head to contact a secondcomponent of the cartridge tip different from the first component and asecond return channel, disposed in the insulator body, configured toconduct at least a portion of the first fluid flow from the secondcomponent to the torch head. The second cooling channel and the secondreturn channel can be non-concentric in relation to the centrallongitudinal axis of the insulator body.

In some embodiments, the consumable cartridge frame further includes atleast one gas channel, disposed in the insulator body, configured toconduct a second fluid flow to a second component of the cartridge tip.The at least one gas channel is non-concentric with respect to thecentral longitudinal axis of the insulator body. The second fluid flowcan comprise a plasma gas flow or a shield gas flow. The secondcomponent can comprise one of a nozzle or shield.

In some embodiments, the first fluid flow comprises a liquid coolantflow. In some embodiments, the component of the cartridge tip comprisesone of a nozzle or shield. In some embodiments, the first coolingchannel and the first return channel extend longitudinally from aproximal region to a distal region of the insulator body and arenon-overlapping.

In another aspect, a cartridge frame for a liquid-cooled plasma arctorch cartridge consumable is provided. The cartridge frame includes acartridge frame body having a central region, an internal surface, anexternal surface, a proximal portion and a distal portion, where thecartridge frame body is at least substantially made of a non-conductivematerial. The cartridge frame also includes a torch engagement interfacesurface located at the proximal portion of the cartridge frame body, thetorch engagement interface surface configured to engage a torch head.The cartridge frame further includes a plurality of component alignmentfeatures formed in the central region and a plurality of channelsbetween the proximal portion and the distal portion. The plurality ofchannels are located offset from a central axis of the central region.The plurality of channels are configured to direct liquid and gasthrough the cartridge frame.

In some embodiments, one or more of the component alignment features areconfigured to align a nozzle to the internal surface of the cartridgeframe and matingly engage the nozzle to the internal surface. The one ormore component alignment features can comprise one or more stepsconfigured to axially align and matingly engage the nozzle to thecartridge frame. The one or more component alignment features cancomprise a varying diameter along a section of the internal surface ofthe cartridge frame to radially align and matingly engage the nozzle tothe cartridge frame. In some embodiments, one or more of the componentalignment features are configured to align a shield to the externalsurface of the cartridge frame and matingly engage the shield to theexternal surface.

In some embodiments, the plurality of channels comprises a shield gaschannel configured to provide a metered shield gas flow therethrough.The cartridge frame can further include a baffle and a shield swirl ringdisposed at the distal portion of the cartridge frame body. The baffleand the shield swirl ring can be in fluid communication with the shieldgas channel to adjust at least one parameter of the shield gas flowtherethrough.

In some embodiments, the cartridge frame further includes an opening onthe internal surface of the cartridge frame. The plurality of channelsinclude a coolant channel configured to supply a liquid coolant to anozzle, and the opening is in fluid communication with the coolantchannel to conduct the liquid coolant away from the nozzle. In someembodiments, the cartridge frame further includes an opening on theexternal surface of the cartridge frame. The plurality of channelsinclude a coolant channel configured to supply a liquid coolant to ashield, and the opening is in fluid communication with the coolantchannel to conduct the liquid coolant away from the shield.

In some embodiments, the cartridge frame further includes a vent passageextending from the internal surface to the external surface of thecartridge frame.

In another aspect, a consumable cartridge for a liquid-cooled plasma arctorch is provided. The consumable cartridge includes a body portionhaving a distal region and a proximal region, a tip portion located atthe distal region the tip portion including a plasma emitter and aplasma arc constrictor, and two or more non-concentric channelsextending from the proximal region to the tip portion in the distalregion of the body.

In some embodiments, the two or more non-concentric channels aredisposed in a cartridge frame made of an insulator material. In someembodiments, the cartridge frame forms an interface between the tipportion and a torch head.

In some embodiments, the tip portion comprises at least one of a nozzle,a shield or an electrode. In some embodiments, the two or morenon-concentric channels include (i) a first set of channels including acoolant channel and a return channel in fluid communication with thenozzle to supply a liquid coolant to and from the nozzle and (ii) asecond set of channels including a coolant channel and a return channelin fluid communication with the shield to supply at least a portion ofthe liquid coolant to and from the shield. In some embodiments, the twoor more non-concentric channels include a plasma gas channel to supply aplasma gas to a passage between a swirl ring and the nozzle. In someembodiments, the two or more non-concentric channels include a shieldgas channel to supply a shield gas to a passage between the shield andthe nozzle. In some embodiments, the consumable cartridge furtherincludes a central channel in fluid communication with the electrode,where the central channel is configured to pass at least one of a liquidcoolant or an electrical current to the electrode.

In another aspect, a consumable cartridge frame for a liquid-cooledplasma arc torch is provided. The consumable cartridge frame includes afirst interface configured to connect to a torch head of the plasma arctorch, and a second interface spaced axially relative the first surfacealong a longitudinal axis of the consumable, where the second interfaceis configured to connect to a plurality of components including at leasta nozzle, a shield, an electrode, and a swirl ring. The consumablecartridge frame further includes a body portion extending along thelongitudinal axis to connect the first interface with the secondinterface. The body portion includes a plurality of channels configuredto convey liquid and gas between the torch head and the plurality ofcomponents through the first interface and the second interface.

In some embodiments, the first interface includes an alignment featureconfigured to radially secure to the torch head in a predeterminedorientation. The plurality of channels can be adapted to align withcorresponding channels in the torch head in the predeterminedorientation to convey liquid and gas between the torch head and theplurality of components. In some embodiments, two or more of theplurality of channels are non-concentric.

In some embodiments, the second interface comprises (i) at least onestep on an internal surface of the consumable cartridge frame tomatingly engage and axially align the nozzle to the cartridge frame and(ii) at least one section of the internal surface of the consumablecartridge frame with varying diameter to matingly engage and radiallyalign the nozzle to the cartridge frame. The second interface can alsoinclude alignment features configured to axially and radially align theshield with the cartridge frame and matingly engage the shield to thecartridge frame. The alignment features can comprise at least one of astep or a mating section on an external surface of the consumablecartridge.

In some embodiments, the consumable cartridge frame can further includea cavity disposed in the body portion adjacent to the first interface.The cavity is configured to receive a radio-frequency identification(RFID) tag for communicating with a reader device of the torch head.

In yet another aspect, a cartridge frame for a liquid cooled plasma arctorch cartridge consumable is provided. The cartridge frame includes acartridge frame body having a proximal portion, a distal portion, anexterior surface, and an internal opening to a central channel in thecartridge frame body. The cartridge frame also includes a shield gaschannel extending from the proximal portion of the cartridge frame bodyto the distal portion of the cartridge frame body, a nozzle coolantsupply channel extending from the proximal portion of the cartridgeframe body to the internal opening, and a nozzle coolant return channelextending from the internal opening of the cartridge frame body to theproximal portion. The cartridge frame further includes a circumferentialcoolant flow channel in the exterior surface of the cartridge framebody, a shield coolant supply channel extending from the proximalportion to the circumferential coolant flow channel, and a shieldcoolant return channel extending from the circumferential coolant flowchannel to the proximal portion.

In yet another aspect, a liquid-cooled consumable cartridge for a plasmaarc torch is provided. The cartridge includes (i) an electrode, (ii) aswirl ring with a first outer retaining feature and a second outerretaining feature on an exterior surface, where the electrode is securedto the swirl ring, and (iii) a nozzle with an inner retaining feature onan interior surface, where the inner retaining feature of the nozzle ismated with the first outer retaining feature of the swirl ring. Thecartridge also includes a cartridge frame with an inner retainingfeature on an interior surface and an outer retaining feature on anexterior surface. The inner retaining feature of the cartridge frame ismated with the second outer retaining feature of the swirl ring. Thecartridge further includes a shield with an inner retaining feature onan interior surface mated with the outer retaining feature of thecartridge frame. At least the nozzle, the swirl ring, the cartridgeframe and the shield are axially secured in a predetermine position uponmating with each other to provide at least one liquid flow path from thecartridge frame to the shield or the nozzle.

In some embodiments, the electrode and the nozzle are axially andradially aligned relative to each other without physical contact betweenthe electrode and the nozzle. In some embodiments, the nozzle and theshield are axially and radially aligned relative to each other withoutphysical contact between the nozzle and the shield.

In some embodiments, at least one of the shield, the nozzle, or theswirl ring mates directly with the cartridge frame. The electrode can beindirectly mated with the cartridge frame via at least one of the swirlring or an electrode insulator.

In some embodiments, mating between the inner retaining feature of thenozzle and the first outer retaining feature of the swirl ring radiallyaligns the nozzle with the swirl ring. In some embodiments, matingbetween the inner retaining feature of the cartridge frame and thesecond outer retaining feature of the swirl ring provides at least oneof axial or radial alignment between the cartridge frame and the swirlring. In some embodiments, mating between an inner retaining feature ofthe shield and the outer retaining feature of the cartridge frameprovides at least one of axial or radial alignment between the cartridgeframe and the shield. In some embodiments, the cartridge frame furthercomprises a second inner retaining feature on the interior surfaceconfigured to be mated with an outer retaining feature on an outersurface of the nozzle. The mating between the cartridge frame and thenozzle provides at least one of axial or radial alignment between thecartridge frame and the nozzle.

In some embodiments, the nozzle is a non-vented nozzle coupled to anozzle jacket. In some embodiments, the nozzle is a vented nozzlecoupled to a nozzle liner.

In yet another aspect, a liquid-cooled consumable cartridge for a plasmaarc torch is provided. The cartridge includes (i) an electrode, (ii) aswirl ring with an outer retaining feature on an exterior surface and aninner retaining feature on an interior surface, where the electrode issecured to the inner retaining surface of the swirl ring, and (iii) anozzle with an outer retaining feature on an outer surface. Thecartridge also includes a cartridge frame with a first inner retainingfeature and a second inner retaining feature on an interior surface andan outer retaining feature on an exterior surface. The first innerretaining feature of the cartridge frame is mated with the outerretaining feature of the swirl ring and the second inner retainingfeature of the cartridge frame is mated with the outer retaining featureof the nozzle. The cartridge further includes a shield with an innerretaining feature on an interior surface mated with the outer retainingfeature of the cartridge frame. At least the nozzle, the swirl ring, thecartridge frame and the shield are axially secured in a predeterminedposition upon mating.

In yet another aspect, a consumable cartridge for a liquid-cooled plasmaarc torch is provided. The consumable cartridge includes anon-conductive cartridge frame, and a set of conductive consumablecomponents defining, in part, a plasma plenum. The set of conductivecomponents are affixed to the cartridge frame. The consumable cartridgeis composed of at least 50% non-conductive material by volume. In someembodiments, the consumable cartridge is composed of about 60% to about80% non-conductive material by volume.

In some embodiments, the consumable cartridge is a single use cartridge.The set of conductive consumable components may not be individuallydisposable or serviceable after being affixed to the cartridge frame.

In some embodiments, the cartridge frame comprises liquid and gaschannels in fluid communication with the set of conductive components.The liquid and gas channels are non-concentric in relation to a centrallongitudinal axis of the cartridge frame.

In some embodiments, the set of conductive consumable componentscomprises a shield, a nozzle and an electrode.

In another aspect, a method of manufacturing a unitary consumablecartridge from a plurality of components is provided. The methodincludes axially and radially securing an electrode to a swirl ring,axially and radially securing a retaining feature on an outer surface ofthe swirl ring to at least one of a mated retaining feature on an innersurface of a cartridge frame or a nozzle, and axially and radiallysecuring a retaining feature on an outer surface of the cartridge frameto a mated retaining feature on an inner surface of a shield. The axialand radial securing of the consumable components relative to each otherpositions at least one internal fluid channel of the cartridge framewith (i) a fluid passage of the nozzle or (ii) a fluid passage of theshield.

In some embodiments, axially and radially securing an electrode to aswirl ring comprises axially and radially securing the electrode to anelectrode insulator and axially and radially securing the electrodeinsulator to the swirl ring.

In some embodiments, the method further comprises radially aligning aplasma gas channel within the cartridge frame with a gas passage betweenthe swirl ring and the nozzle. In some embodiments, the method furthercomprises radially aligning a shield gas channel within the cartridgeframe with a gas passage between the nozzle and the shield. In someembodiments, the method further comprises radially aligning a centralchannel within the cartridge frame with the electrode. In someembodiments, the method further comprises radially aligning a firstcoolant channel and a second coolant channel within the cartridge framewith the nozzle, and radially aligning a third coolant channel and afourth coolant channel within the cartridge frame with the shield.

In some embodiments, the method further comprises forming the swirl ringthrough die cast using zinc. In some embodiments, the method furthercomprises forming the cartridge frame through molding using anon-conductive material. In some embodiments, the method furthercomprises forming the shield through stamping using a conductivematerial. In some embodiments, the axial and radial securing of theplurality of components is through one or more of snap fit, press fit orinterference, crimping, gluing, cementing or welding.

In another aspect, a method of assembling a liquid cooled consumablecartridge for a plasma arc cutting torch is provided. The methodincludes providing an insulator cartridge frame having a central region,an outer surface, a distal end, and a proximal end. The method furtherincludes coupling a swirling component to the cartridge frame in thecentral region, coupling an electrode to the cartridge frame in thecentral region, coupling a nozzle to the cartridge frame in the centralregion, and coupling a shield to the cartridge frame at the outersurface.

In some embodiments, coupling a swirling component to the cartridgeframe comprises mating an exterior surface of the swirling component toan interior surface of the cartridge frame that provides at least one ofaxial or radial alignment of the swirling component to the cartridgeframe. In some embodiments, coupling a nozzle to the cartridge framecomprises coupling an exterior surface of the nozzle to an interiorsurface of the cartridge frame that provides at least one of axial orradial alignment of the nozzle to the cartridge frame. In someembodiments, coupling a shield to the cartridge frame at the outersurface provides at least one of axial or radial alignment of the shieldto the cartridge frame. In some embodiments, the method furthercomprises coupling the electrode to the cartridge frame via at least oneof the swirling component and an electrode insulator. In someembodiments, the coupling aligns at least one internal fluid channel ofthe cartridge frame with (i) a fluid passage of the nozzle or (ii) afluid passage of the shield.

In some embodiments, the method further comprises disposing a baffle anda second swirling component at a distal end of the cartridge frame inthe central region.

A consumable cartridge for a liquid-cooled plasma arc torch is provided.The consumable cartridge comprises a cartridge frame including aproximal end having an end surface, a distal end and a body having acentral longitudinal axis extending therethrough. The cartridgeconfigured to form a radio-frequency identification (RFID) interfacewith a torch head. The consumable cartridge also comprises an arcemitter and an arc constrictor affixed to the cartridge frame at thedistal end and an RFID mounting feature formed on or in the cartridgeframe adjacent to the end face. The RFID mounting feature isnon-concentric with the central longitudinal axis of the body. Theconsumable cartridge further comprises an RFID tag disposed in or on theRFID mounting feature for transmitting information about the cartridgeto a reader device in the torch head when the cartridge is connected tothe torch head, and a clocking feature configured to rotationally alignthe RFID tag to the reader device in the torch head upon connection ofthe cartridge to the torch head.

In some embodiments, the RFID mounting feature comprises a cavitydisposed in the body of the cartridge frame. The RFID tag can beembedded in the cavity of the body of the cartridge frame and surroundedby an insulator material of the body. In some embodiments, the endsurface is substantially planar to allow an RFID reader to interrogatethe RFID tag from outside of the plasma arc torch. In some embodiments,the RFID tag is readable from inside or outside of the plasma arc torch.

In some embodiments, the body of the cartridge frame is constructed froman insulator material. In some embodiments, the body of the cartridgeframe comprises at least one channel for conducting a liquid coolanttherethrough. The at least one channel can be configured tosubstantially align with a corresponding channel of the torch head uponthe rotational alignment by the clocking feature to conduct the liquidcoolant between the torch head and the cartridge.

In some embodiments, upon the rotational alignment, the RFID tag in thecartridge frame and the reader device in the torch head are orientedsuch that a central axis extends through a centerline of the RFID tagand a centerline of the reader device. In some embodiments, upon therotational alignment, a first distance between the RFID tag and thereader device is less than a second distance between the RFID tag andadjacent metallic material disposed in the torch head or the cartridge.

In some embodiments, the clocking feature comprises a cavity configuredto receive a clocking pin extending from the torch head.

In yet another aspect, a consumable cartridge for a liquid-cooled plasmaarc cutting torch is provided. The consumable cartridge includes acartridge tip located at a first portion of the cartridge. The cartridgetip has an electrode, a nozzle, and a shield. The consumable cartridgeincludes a plasma gas inlet opening at a second portion of theconsumable cartridge, a shield gas inlet opening at the second portion,an electrode coolant inlet opening at the second portion, a nozzlecoolant inlet opening and a nozzle coolant outlet opening at the secondportion, and a shield coolant inlet opening and a shield coolant outletopening at the second portion.

In some embodiments, the second portion comprises an end face of aproximal portion of the cartridge. The end face can be substantiallyplanar.

In some embodiments, the plasma gas inlet opening, the shield gas inletopening, the nozzle coolant inlet opening, the nozzle coolant outletopening, the shield coolant inlet opening and the shield coolant outletopening are non-concentric relative to a central longitudinal axis ofthe cartridge.

In some embodiments, the plasma gas inlet opening is configured to alignwith a corresponding opening of a torch head to direct a plasma gas flowfrom the torch head to the nozzle. In some embodiments, the shield gasinlet opening is in fluid communication with the shield. The shield gasinlet opening is configured to align with a corresponding opening of atorch head to direct a shield gas flow to the shield. In someembodiments, the electrode coolant inlet opening maintains at least oneof electrical or fluid communication with the electrode. The electrodecoolant inlet opening is configured to align with a correspondingopening of a torch head to direct at least one of a liquid coolant or acurrent to the electrode. In some embodiments, the nozzle coolant inletopening and the nozzle coolant outlet opening are in fluid communicationwith the nozzle. The nozzle coolant inlet opening and the nozzle coolantoutlet opening are configured to align with respective ones ofcorresponding openings on the torch head to direct the liquid coolantbetween the torch head and the nozzle. In some embodiments, the shieldcoolant inlet opening and the shield coolant outlet opening are in fluidcommunication with the shield. The shield coolant inlet opening and theshield coolant outlet opening are configured to align with respectiveones of corresponding openings on the torch head to direct the liquidcoolant between the torch head and the shield. In some embodiments, thenozzle coolant outlet opening is fluidly connected to the shield coolantinlet opening.

In some embodiments, the consumable cartridge further comprises aclocking pin receptacle at the second portion. The clocking pinreceptacle is configured to receive a clocking pin of a torch head toradially secure the cartridge to the torch head in a predeterminedorientation.

In some embodiments, the consumable cartridge further comprises acartridge frame having an insulator body. The cartridge frame is coupledto the cartridge tip. The plasma gas inlet opening, the shield gas inletopening, the electrode coolant inlet opening, the nozzle coolant inletopening, the nozzle coolant outlet opening, the shield coolant inletopening and the shield coolant outlet opening are located at a proximalend of the insulator body. In some embodiments, the consumable cartridgefurther comprises a non-concentric cavity disposed in the insulator bodyof the cartridge frame and a radio-frequency identification (RFID) tagdisposed in the cavity.

In yet another aspect, a consumable cartridge for a liquid-cooled plasmaarc cutting torch is provided. The consumable cartridge includes acartridge tip located at a first portion of the cartridge. The cartridgetip has an electrode, a nozzle, and a shield. The consumable cartridgealso includes a cartridge frame at a second portion of the cartridge.The cartridge frame comprises a distal end connected to the cartridgetip and a proximal end. The cartridge frame includes a plasma gas inletopening at the proximal end configured to maintain fluid communicationwith the nozzle to introduce a plasma gas flow to the nozzle, a shieldgas inlet opening at the proximal end configured to maintain fluidcommunication with the shield to introduce a shield gas flow to theshield, and an electrode interface at the proximal end configured tomaintain at least one of electrical or fluid communication with theelectrode to introduce at least one of a coolant flow or electricalcurrent to the electrode. The cartridge frame further includes a nozzlecoolant inlet opening and a nozzle coolant outlet opening at theproximal end configured to circulate the coolant flow between thecartridge frame and the nozzle and a shield coolant inlet opening and ashield coolant outlet opening at the proximal end configured tocirculate the coolant flow between the cartridge frame and the shield.

In another aspect, a torch head for a liquid-cooled plasma arc torch isprovided. The torch head includes a torch body and a torch insulatorhaving a substantially non-conductive insulator body. The torchinsulator is coupled to the torch body. The torch insulator includes (i)a first liquid coolant channel, disposed within the insulator body,configured to conduct a fluid flow from the torch head into a consumablecartridge along a first preexisting flow path, (ii) a first liquidreturn channel, disposed within the insulator body, configured to returnat least a portion of the fluid flow from the cartridge to the torchhead along the first preexisting flow path, and (iii) a gas channel,disposed within the insulator body, configured to conduct a first gasflow from the torch head to the cartridge along a second preexistingflow path. The first and second preexisting flow paths are fluidlyisolated from each other.

In some embodiments, the torch head further comprises an alignmentfeature configured to radially secure the torch head to the cartridge ina predetermined orientation to maintain the first and second preexistingflow paths extending through the torch insulator and the cartridge. Thefirst liquid coolant channel can be configured to substantially alignwith a corresponding first liquid coolant channel of the cartridge whenthe torch head is radially secured to the cartridge via the alignmentfeature. The first liquid return channel can be configured tosubstantially align with a corresponding first liquid return channel ofthe cartridge when the torch head is radially secured to the cartridgevia the alignment feature. The first preexisting flow path can comprisethe first liquid coolant channel of the torch head, the correspondingfirst liquid coolant channel of the cartridge, the corresponding firstliquid return channel of the cartridge and the first liquid returnchannel of the torch head.

In some embodiments, the torch insulator further comprises a gas valveembedded in the insulator body, the gas valve in fluid communicationwith the gas channel, the gas valve configured to select one of aplurality of gases for supply to the gas channel. In some embodiments,the torch insulator further comprises a second gas channel, disposedwithin the insulator body, configured to conduct a second gas flow fromthe torch head to the cartridge along a third preexisting flow path. Thesecond and third preexisting flow paths are fluidly isolated from eachother. In some embodiments, the torch insulator further comprises acentral channel disposed in the insulator body, the central channelconfigured to provide at least one of (i) a current or (ii) at least aportion of the fluid flow from the torch head to the cartridge. In someembodiments, the torch insulator further comprises an electrical channeldisposed in the insulator body, the electrical channel configured toreceive an ohmic contact connection that establishes an ohmic contactbetween the torch head and the cartridge.

In some embodiments, the torch insulator further comprises (i) a currentring at a distal end of the insulator body, the current ring configuredto receive a pilot arc current from the cartridge, and (ii) a pilot arcchannel configured to receive a pilot arc connection that is inelectrical communication with the current ring to pass the pilot arccurrent from the cartridge to the torch head.

In some embodiments, the torch insulator further comprises (i) a secondliquid coolant channel, disposed within the insulator body, configuredto conduct at least a portion of the fluid flow from the torch head intothe cartridge along the first preexisting flow path, (ii) a secondliquid return channel, disposed within the insulator body, configured toreturn at least a portion of the fluid flow from the cartridge to thetorch head along the first preexisting flow path, and (iii) adistribution channel, disposed within the insulator body, connecting thefirst liquid return channel with the second liquid coolant channel. Thefirst preexisting flow path can flow over a sequence of channels in theinsulator body comprising the first liquid coolant channel, the firstliquid return channel, the distribution channel the second liquidcoolant channel, and the second liquid return channel.

In some embodiments, the first liquid coolant channel, the first liquidreturn channel and the gas channel are non-concentric with respect to alongitudinal axis extending through the insulator body.

In another aspect, a torch head for a liquid-cooled plasma arc torch isprovided. The torch head includes (i) a torch insulator having aninsulator body, (ii) a first cooling channel and a third coolingchannel, disposed in the insulator body, each configured to conduct afirst fluid flow from the torch head into a cartridge, (iii) a secondcooling channel and a fourth cooling channel, disposed in the insulatorbody, each configured to return at least a portion of the first fluidflow from the cartridge to the torch head, and (iv) a first distributionchannel, disposed in the insulator body, connecting the second coolingchannel and the third cooling channel. The first distribution channel isconfigured to direct the first fluid flow from the second channel to thethird channel.

In some embodiments, the first distribution channel is circumferentiallyoriented to connect the second cooling channel and the third coolingchannel. In some embodiments, the first, the second, the third and thefourth cooling channels are non-concentric about a longitudinal axisextending through the insulator body. In some embodiments, each of thefirst, the second, the third and the fourth cooling channels areasymmetric with respect to a central longitudinal axis extending throughthe insulator body.

In yet another aspect, a torch head for a liquid-cooled plasma arc torchis provided. The torch head includes (i) a torch insulator having aninsulator body including a proximal end and a distal end, (ii) aplurality of gas and liquid channels extending substantially from theproximal end to the distal end of the insulator body, (iii) a cavity inthe insulator body, and (iv) a communication device comprising a circuitboard and a radio-frequency identification (RFID) antenna coil. The RFIDantenna coil is electrically connected to the circuit board andpositioned adjacent a distal end of the communication device. Thecommunication device is located in the cavity such that the RFID antennacoil is positioned at the distal end of the insulator body.

In some embodiments, the communication device further comprises a sealedhousing for preventing liquid from entering therein. In someembodiments, the circuit board of the communication device is configuredto power the antenna coil and read an RFID signal received by theantenna coil. The antenna coil can be positioned at an end face of thedistal end of the communication device. In some embodiments, thecommunication device further comprises a connector at a proximal end ofthe communication device.

In some embodiments, the plurality of gas and liquid channels and thecavity are non-concentric in relation to a central longitudinal axis ofthe insulator body.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the invention described above, together with furtheradvantages, may be better understood by referring to the followingdescription taken in conjunction with the accompanying drawings. Thedrawings are not necessarily to scale, emphasis instead generally beingplaced upon illustrating the principles of the invention.

FIGS. 1a and 1b are exploded and assembled views, respectively, of aliquid-cooled plasma arc torch 10 generally comprising a torch head anda cartridge, according to an illustrative embodiment of the invention.

FIG. 2 is a cross-sectional view of the assembled plasma arc torch ofFIG. 1b , according to an illustrative embodiment of the invention.

FIG. 3 is a view of the proximal end of the torch head of FIG. 1,according to an illustrative embodiment of the invention.

FIG. 4 is a view of the distal end of the torch head of FIG. 1,according to an illustrative embodiment of the invention.

FIG. 5 is an exemplary design of the cathode of the torch head of FIG.1, according to an illustrative embodiment of the invention.

FIG. 6 is an exemplary design of the coolant tube of the torch head ofFIG. 1, according to an illustrative embodiment of the invention.

FIG. 7 is a sectional view of the plasma arc torch of FIG. 2 oriented toillustrate an exemplary pilot arc current flow path between the torchhead and the cartridge of the plasma arc torch, according to anillustrative embodiment of the present invention.

FIG. 8 is a sectional view of the plasma arc torch of FIG. 2 oriented toillustrate an exemplary ohmic contact path, according to an illustrativeembodiment of the present invention.

FIG. 9 is an exemplary design of the current ring in the torch head ofFIG. 1, according to an illustrative embodiment of the presentinvention.

FIG. 10 is an exemplary design of the communication device of the torchhead 102, according to an illustrative embodiment of the presentinvention.

FIGS. 11a and b are sectional views of the plasma arc torch of FIG. 2oriented to illustrate an exemplary shield gas flow path from the torchhead to the cartridge of the plasma arc torch, according to anillustrative embodiment of the present invention.

FIGS. 12a-c are sectional views of the plasma arc torch of FIG. 2oriented to illustrate an exemplary plasma gas flow path from the torchhead to the cartridge of the plasma arc torch, according to anillustrative embodiment of the present invention.

FIGS. 13a and b are sectional views of the plasma arc torch of FIG. 2oriented to illustrate an exemplary liquid coolant flow path thatcirculates between the torch head and the cartridge of the plasma arctorch, according to an illustrative embodiment of the present invention.

FIGS. 14a and b are exemplary profile and proximal views of the cathodeblock of the torch head, respectively, according to an illustrativeembodiment of the present invention.

FIG. 15 is a view of the proximal end of the cartridge frame of thecartridge of FIG. 1, according to an illustrative embodiment of thepresent invention.

FIG. 16 is a sectional view of an exemplary design of the retaining cap120 of FIG. 1, according to an illustrative embodiment of the presentinvention.

FIG. 17 is a sectional view of the cartridge of FIG. 1, according to anillustrative embodiment of the present invention.

FIG. 18 is an exemplary design of the cartridge frame of the cartridgeof FIG. 17, according to an illustrative embodiment of the presentinvention.

FIG. 19 is an exemplary design of the electrode of the cartridge of FIG.17, according to an illustrative embodiment of the present invention.

FIG. 20 is a cross-sectional view of the baffle and the shield swirlring attached to the cartridge frame of the cartridge of FIG. 17,according to an illustrative embodiment of the present invention.

FIG. 21 is a cross-sectional view of the shield swirl ring of thecartridge of FIG. 17, according to an illustrative embodiment of thepresent invention.

FIG. 22 is a perspective view of the cartridge frame of the cartridge ofFIG. 17 illustrating various channel openings, according to anillustrative embodiment of the present invention.

FIG. 23 is an exemplary design of the swirl ring of the cartridge ofFIG. 17, according to an illustrative embodiment of the presentinvention.

FIGS. 24a and b are exterior views of the non-vented nozzle and thenozzle jacket of the cartridge of FIG. 17, respectively, according to anillustrative embodiment of the present invention.

FIG. 25 is a cross sectional view of the shield of the cartridge of FIG.17, according to an illustrative embodiment of the present invention.

FIG. 26 is an exemplary vented cartridge compatible with the torch headof the plasma arc torch of FIG. 1, according to an illustrativeembodiment of the present invention.

FIGS. 27a and b are exterior views of the nozzle liner and the ventednozzle of the cartridge of FIG. 26, respectively, according to anillustrative embodiment of the present invention.

FIG. 28 is another exemplary cartridge frame that can be suitablyconfigured to form a cartridge compatible with the torch head of FIG. 1,according to an illustrative embodiment of the present invention.

FIG. 29 is an exemplary vented cartridge that includes a non-planarproximal end, according to an illustrative embodiment of the presentinvention.

FIG. 30 is an exploded view of the cartridge of FIG. 17, according to anillustrative embodiment of the present invention.

FIG. 31 is a portion of the plasma arc torch of FIG. 2 illustratingexemplary locations of the communication device and the signal device,according to an illustrative embodiment of the present invention.

DETAILED DESCRIPTION

The present invention provides a liquid-cooled plasma arc torch thatincludes a torch head and a consumable cartridge. In some embodiments,the consumable cartridge is a unitary component where the components ofthe cartridge are not individually serviceable or disposable. Thus, ifone component of the consumable cartridge needs to be replaced, theentire cartridge is replaced. In some embodiments, the consumablecartridge is a “single use” cartridge, where the cartridge is replacedby the operator after any of the components thereof reaches the end ofits service life rather than repairing and replacing the individualconsumables like in traditional torch designs. In some embodiments, thecartridge is replaced after a single session, which can involve multiplearcs. In some embodiments, the cartridge is replaced after a single arcevent.

FIGS. 1a and 1b are exploded and assembled views, respectively, of aliquid-cooled plasma arc torch 10 generally comprising a torch head 102and a cartridge 104, according to an illustrative embodiment of theinvention. The cartridge 104, which comprises a plurality of consumabletorch components, has a proximal end (region) 14 and a distal end(region) 16 along a central longitudinal axis A of the plasma arc torch10. The torch head 102 includes a torch body 18, a proximal end (region)20 and a distal end (region) 22 along the longitudinal axis A. The torchbody 18 can be made of an electrically conductive material, such asbrass. In some embodiments, the proximal end 14 of the cartridge 104 isaligned with and secured to the distal end 22 of the torch head 102 by aretaining cap 120. In some embodiments, the proximal end 14 of thecartridge 104 matingly engages/connects to the distal end 22 of torch102. For example, the proximal end 14 and the distal end 22 can beconnected via at least seven distinct mating joints/junctions/connectionpoints. Other engagement means between the torch head 102 and cartridge104 are possible, including threading, interference fit, snap fit, quicklock, etc. Hereinafter, a proximal end of a component defines a regionof the component along the longitudinal axis A that is away from aworkpiece when the torch 10 is used to process the workpiece, and adistal end of the component defines a region of the component that isopposite of the proximal end and close to the workpiece when the torch10 is used to process the workpiece.

FIG. 2 is a cross-sectional view of the assembled plasma arc torch 10 ofFIG. 1b , according to an illustrative embodiment of the invention. Asshown, an interface 106 in FIG. 1 defines the boundary between thecartridge 104 and the torch head 102 after they are engaged to eachother. The cartridge 104, which is a substantially unitary element,includes a cartridge tip comprising an electrode 108 (i.e., an arcemitter), a nozzle 110 (i.e., an arc constrictor) and a shield 114disposed concentrically about the central longitudinal axis A.Components of the cartridge tip can be connected to a cartridge frame112 of the cartridge 104. In some embodiments, the cartridge 104 alsoincludes a swirl ring 150 disposed about the longitudinal axis A.Details regarding the cartridge 104 are explained below with referenceto FIGS. 15 and 17-25. The torch head 102 includes a torch insulator 118disposed in the torch body 18 about the longitudinal axis A. Detailsregarding the torch head 102 are explained below with reference to FIGS.2-14 b.

Torch Head

As shown in FIG. 2, the torch insulator 118 of the torch head 102 issubstantially disposed in and surrounded by the torch body 18 about thecentral longitudinal axis A. The torch body 18 can be made of anelectrically conductive material, such as brass. The torch insulator118, which include a proximal end 21 and a distal end 23, can be made ofan electrically insulating material, such as plastic. The torchinsulator 118, at its proximal end 21, can couple to one or more of acathode 130, a communication device 122, a pilot arc connection 124 andan ohmic connection 131 while electrically insulating these componentsfrom each other and from the torch body 18. In some embodiments, atleast one of the cathode 130, the communication device 122, the pilotarc connection 124, or the ohmic connection 131 is fixed to the torchinsulator 118 (e.g., threaded to or embedded in the torch insulator 118)such that they cannot be easily or quickly disconnected from the torchinsulator 118. In addition, the torch insulator 118 can include at leastone gas opening 126 a for coupling to a source of gas (not shown) andintroducing the gas to the torch 10. The torch insulator 118 can furtherinclude at least one coolant opening 128 a for coupling to a source ofliquid coolant (not shown) and introducing the coolant to the torch 10.FIG. 3 is a view of the proximal end 20 of the torch head 102, whichshows various electrical, gas and liquid openings at the proximal end 21of the torch insulator 118, according to an illustrative embodiment ofthe invention. FIG. 4 is a view of the distal end 22 of the torch head102, which shows various electrical, gas and liquid openings at thedistal end 23 of the torch insulator 118, according to an illustrativeembodiment of the invention.

a. Pilot Arc and Transferred Arc Connection

In one aspect, the torch insulator 118 can interconnect a plurality ofcomponents that are used to maintain a pilot arc current and/or atransferred arc current between the torch head 102 to the cartridge 104.For example, the torch insulator 118 is adapted to connect the cathode130, a coolant tube 116, the pilot arc connection 124 and a current ring800 in a configuration that supports both pilot arc current andtransferred arc current conduction between the torch head 102 and thecartridge 104.

In some embodiments, the torch insulator 118 includes a main channel 132(shown in FIG. 2) extending from an opening 132 a at the proximal end 21of the torch insulator 118 (shown in FIG. 3) to an opening 132 b at thedistal end 23 of the torch insulator 118 (shown in FIG. 4). The mainchannel 132 can be centrally located within the torch insulator 118 suchthat it is concentric with respect to the central longitudinal axis A.The main channel 132 can extend substantially straight within theinsulator 118 to connect the openings 132 a and 132 b. The main channel132 can be configured to house at least a portion of the cathode 130. Asshown in FIG. 2, the cathode 130 can extend within the main channel 132along the length of the torch insulator 118. In some embodiments, acathode block locking component 250 is used to secure the cathode 130 tothe main channel 132 inside of the torch insulator 118.

FIG. 5 is an exemplary design of the cathode 130 of the torch head 102,according to an illustrative embodiment of the invention. The cathode130 includes a cathode fitting 602 with a distal end coupled to acathode tube 604, which has a distal end coupled to a cathode block 606.Each of the cathode fitting 602, the cathode tube 604 and the cathodeblock 606 can be made from a conductive material, such as brass orcopper. In one exemplary design, the cathode fitting 602 and the cathodeblock 606 are made of brass, while the cathode tube 604 is made ofcopper.

As shown in FIG. 2, the distal end of the cathode block 606 canelectrically and/or physically couple to the coolant tube 116 within themain channel 132 of the torch insulator 118. In some embodiments, thecoolant tube 116 defines an o-ring groove that houses an o-ring 133 toform an interface between an outer surface of the coolant tube 116 andan inner surface of the cathode block 606. Thus, at least a proximalportion of the coolant tube 116 is inserted within the distal end of thecathode block 606. Generally, during operation the coolant tube 116distributes a cooling fluid to the cartridge 104 once the torch head 102is coupled to the cartridge 104. In some embodiments, the coolant tube116 is configured to additionally pass a current from the cathode 130 tothe cartridge 104, such as to the electrode 108 of the cartridge 104. Insome embodiments, a cathode block electrode tube 252 (shown in FIG. 2),which can be made of a non-conductive material, can be configured toconnect with (e.g., threaded into or sealed by interference fit) thecathode block 606 at its proximal end and with the electrode 108 at itsdistal end. The resulting housing, which comprises the cathode 130, thecathode block electrode tube 252 and the electrode 108, substantiallyencases the coolant tube 116 to contain the coolant flow therein.

FIG. 6 is an exemplary design of the coolant tube 116 of the torch head102, according to an illustrative embodiment of the invention. Thecoolant tube 116 can be made of a conductive material, such as brass. Insome embodiments, the coolant tube 116 is affixed (e.g., by threading)to the distal end of the cathode block 606 such that it cannot be easilyor quickly disconnected. In some other embodiments, the coolant tube 116is affixed (e.g., by an interference fit) to the distal end of thecathode block 606 such that it can be easily or quickly disconnected.The coolant tube 116 can have an electrical connector, such as aLouvertac™ band 702 around an external surface at a proximal end 740,which is the end that is configured to mate with the cathode block 606.The Louvertac band 702 is configured to conduct the cutting currentcarried from the interior surface of the cathode block 606 to theexterior surface of the coolant tube 116 once the proximal end 740 ofthe coolant tube 116 is inserted into and affixed to the distal end ofthe cathode block 606. Alternatively, the coolant tube 116 can befixedly secured to the cathode 130 via threads or other current-carryingmethods without the Louvertac band 702. In some embodiments, the coolanttube 116 has an electrical connector, such as a Louvertac™ band 704,around an exterior surface at a distal end 742 of the coolant tube 116,which is the end that is configured to mate with an internal surface ofthe electrode 108 once the torch head 102 is secured to the cartridge104. In some embodiments, the coolant tube 116 includes one or morelongitudinal channels 744 on its exterior surface below the Louvertacband 704 at the distal end 742 to limit a pressure drop in the coolantflow between the coolant tube 116 and the electrode 108. In addition toconducting electrical current, the coolant tube 116 can be configured toconduct a coolant flow to the electrode 108. For example, the coolanttube 116 has an opening 745 at its proximal end 740 and an opening 746at its distal end 742 for allowing a coolant flow to enter and leave thecoolant tube 116, respectively. In some embodiments, the use of aLouvertac™ band 702 or 704 at one of the distal end 742 or the proximalend 740 or at both ends allows the coolant tube 116 to be slidablycoupled to the torch head 102 and likewise allows a cartridge 104 to beslidably coupled to the coolant tube 116. This feature is describedbelow in detail.

In some embodiments, the torch insulator 118 includes a cavity 148(shown in FIG. 2) with an opening 148 a at the proximal end 21 of thetorch insulator 118 (shown in FIG. 3). As shown in FIG. 2, the cavity148 can be configured to house the pilot arc connection 124. In someembodiments, the cavity 148 extends partially into the torch insulator118 along the longitudinal axis A.

In some embodiments, a current ring 800, made of an electricallyconductive material (e.g., brass), is located in the distal end 23 oftorch insulator 118. FIG. 9 is an exemplary design of the current ring800 of the torch insulator 118 in the torch head 102, according to anillustrative embodiment of the present invention. As shown, the currentring 800 has a ring portion 800 a and a protrusion portion 800 b. Thering portion 800 a has a thin distal rim 802 and the protrusion portion800 b has a distal surface 805. The ring portion 800 a of the currentring 800 can be concentrically situated with respect to the coolant tube116 and the cathode 130 in the torch insulator 118, while the protrusionportion 800 b of the current ring 800 can be oriented such that itelectrically and/or physically contacts the proximal end of the pilotarc connection 124 housed in the cavity 148. In some embodiments, thecurrent ring 800 is electrically insulated from the coolant tube 116 andthe cathode 130 by a cathode insulator 804 (shown in FIG. 2) such thatsubstantially no current is passed between the current ring 800 and thecathode 130 or between the current ring 800 and the coolant tube 116. Insome embodiments, as shown in FIG. 4, at least a surface of the currentring 800 is exposed from the distal end 23 of the torch insulator 118via the main electrical channel opening 132 b such that a component ofthe cartridge 104 can physically contact the current ring 800 once thecartridge 104 is attached to the torch head 102. For example, both thethin distal rim 802 of the ring portion 800 a and the distal surface 805of the protrusion portion 800 b of the current ring 800 can be exposedfrom the opening 132 b.

FIG. 7 is a sectional view of the plasma arc torch 10 of FIG. 2 orientedto illustrate an exemplary pilot arc current flow path 752 between thetorch head 102 and the cartridge 104 of the plasma arc torch 10,according to an illustrative embodiment of the present invention. Tostart a pilot arc, a pilot arc current 752 associated with ahigh-frequency, high-voltage (HFHV) signal is coupled to a power linefrom a power supply (not shown) to the plasma arc torch 10. The pilotarc current flow 752 can be passed from the power supply to the cathode130 via the cathode fitting 602. The cathode tube 604 that is connectedto the cathode fitting 602 then passes the pilot arc current 752 to thecathode block 606, which transfers the current to the coolant tube 116via the Louvertac band 702 at the proximal end 740 of the coolant tube116. The pilot arc current 752 flows distally through the coolant tube116 and is transferred to the internal surface of the electrode 108 viathe Louvertac band 704 at the distal end 742 of the coolant tube 116,thereby energizing the internal surface of the electrode 108. Inalternative embodiments, the pilot arc current is passed from thecathode 130 to the electrode 108 without using the coolant tube 116,such as through a physical connection between the cathode 130 and theelectrode 108. Once at the electrode 108, the pilot arc current path 752induces a spark discharge in a plasma gas flowing in the gap between theelectrode 108 and the nozzle 110, thereby generating a pilot arc in thegap. To complete the pilot arc circuit, the pilot arc current path 752can return to the torch head 102 by flowing proximally from the nozzle110, to the swirl ring 150 (which can be made of a conductive material),and to the current ring 800 in the torch head 102. As shown, the distalend of the swirl ring 150 physically contacts the nozzle 110 at aninterface 758. The proximal end of the swirl ring 150 physicallycontacts at least the distal rim 802 of the ring portion 800 a of thecurrent ring 800 via a Louvertac electrical connector 756. The swirlring 150 is thus configured to return the pilot arc current 752 from thenozzle 110 of the cartridge 104 to the torch head 102. The ring portion800 a of the current ring 800 can transfer the pilot arc current 752 tothe protrusion portion 800 b of the current ring 800, which passes thepilot arc current flow 752 to the pilot arc current connection 124within the cavity 148 to return the pilot arc current to the powersupply.

The gas flow in the gap between the electrode 108 and the nozzle 110 isionized by the pilot arc so that electrical resistance between theelectrode 108 and a workpiece (not shown) becomes small. A voltagehigher than the voltage used to initiate the pilot arc can be appliedacross the electrode 108 and the workpiece to induce the arc to transferto the workpiece after the gap is ionized. This arc between theelectrode 108 and the workpiece is a transferred arc. To maintain thetransferred arc, a transferred arc current, which supplies the highervoltage from the power supply, is passed from the cathode 130 to theelectrode 108 via the coolant tube 116 and the Louvertac bands 702, 704in substantially similar fashion as the distal pilot arc current flow752. To complete the transferred arc circuit, the transferred arccurrent is returned from the workpiece to the power supply throughseparate wirings (not shown).

b. Communication Device (RFID Reader)

In another aspect, the torch insulator 118 can be configured to supportwireless communication between the torch head 102 and the cartridge 104.In some embodiments, the torch insulator 118 includes a cavity 144(shown in FIG. 2) with an opening 144 a at the proximal end 21 of thetorch insulator 118 (shown in FIG. 3). The cavity 144 can be configuredto retain the communication device 122 within the torch insulator 118.The communication device 122 is removable from the cavity 144 via theopening 144 a. In some embodiments, the cavity 144 extends partiallyinto the torch insulator 118 along the central longitudinal axis A suchthat there is no corresponding opening on the distal end 23 of the torchinsulator 118.

FIG. 10 is an exemplary design of the communication device 122 of thetorch head 102, according to an illustrative embodiment of the presentinvention. The communication device 122 can comprise a radio-frequencyidentification (RFID) reader adapted to receive RFID signals wirelesslytransmitted from a nearby signal device 160 (e.g., an RFID tag) locatedin the cartridge 104 (shown in FIG. 2). The communication device 122 isadapted to process these signals to extract pertinent data transmittedby the signal device 160 about the cartridge 104 (and/or other torchinformation) and forward the data to a processor (not shown) foranalysis. In general, the communication device 122 can be placed at alocation in the plasma arc torch 10, such as in the torch insulator 118,to minimize the possibility of plasma arc and arc ignition disruptingthe wireless communication between the signal device 160 and thecommunication device 122. The communication device 122 can include aconnector 806 at its proximal end, an antenna assembly 808 at its distalend, and a processing assembly 810 between the connector 806 and theantenna assembly 808.

The antenna assembly 808 can include an antenna coil 814 configured towirelessly transmit RF signals to the signal device 160 to interrogatethe signal device 160 and/or receive RF signals from the signal device160 in response to the interrogation. This antenna coil 814 can belocated at the distal end of the antenna assembly 808 (i.e., the distalend of the communication device 122) such that when the communicationdevice 122 is inserted into the cavity 144, the antenna coil 814 isembedded at the distal end 23 of the torch insulator 118. Such aplacement minimizes wireless communication distance between the antennacoil 814 and the signal device 160 in the cartridge 104 and reducescommunication interference between them. In some embodiments, theantenna coil 814 is positioned at an end face of the distal end of thecommunication device. For example, the antenna coil 814 can be woundaround the post 812 at the distal end of the antenna assembly 808. Theassembly 808 can also include a plastic cylindrical housing configuredto feed one or more wires connected to the antenna coil 814 to theprocessing assembly 810. The processing assembly 810 can include aplastic cylindrical housing having one or more hardware components(e.g., a printed circuit board (PCB)) disposed therein. The PCB, whichis connected to the wires from the antenna coil 814 of the antennaassembly 808, is configured to (i) power the communication device 122including the antenna assembly 808, (ii) power the signal device 160,and/or (iii) wirelessly communicate with the signal device 160 via theantenna coil 814 using a communication protocol (e.g., an RFID protocolsuch as ISO/IEC 15693) to process data from the signal device 160. Insome embodiments, the PCB can power an entire torch communicationcircuit on board the torch 10 that includes the communication device122, the signal device 160 and related components. The connector 806,which is in electrical communication with the PCB of the processingassembly 810, is configured to transmit the data processed by theprocessing assembly 810 to a computing device (e.g., a centralprocessing unit or the like) external to the torch 10. For example, theconnector 806, in cooperation with the PCB of the processing assembly810, can convey information obtained from the signal device 160 to theexternal computing device using either a wireless or wired connection.

In some embodiments, the circuity that enables wireless communicationbetween the communication device 122 and the signal device 160 is analogwhile the circuitry that enables (wired or wireless) communicationbetween the communication device 122 and the external computing deviceis digital. In this configuration, placing the communication device 122,including the PCB, in the torch 10 reduces the distance of communicationbetween the communication device 122 and the signal device 160 andtherefore reduces noise pickup in the corresponding analog circuitry.However, placing the communication device 122 in the torch 10 canlengthen the communication distance between the communication device 122and the remote computing device, and therefore can increase noise pickupin the corresponding digital circuitry, but the digital circuitry ismore robust (i.e., more immune) to noise pickup than the analogcircuitry.

In some embodiments, the communication device 122 is encased in one ormore layers of protective material providing, for example, electricalinsulation, liquid coolant leakage protection (plus protection fromwaste carried by the coolant flow), and protection against otherenvironmental factors. In some embodiments, the housing of theprocessing assembly 810 and/or the housing of the antenna assembly 808are made of durable plastic to protect the components therein fromliquid and debris. The housings can be translucent such that LED signalsof the PCB therein can be visible from outside of the housings. In someembodiments, one or more o-ring seals are used to protect thecommunication device 122 against liquid damage and create anelectrically insulated barrier.

In some embodiments, the communication device 122 in the torch insulator118 is electrically isolated from the plasma power and ignitioncircuitry, such as by about 30,000 V of electrical isolation. In someembodiments, the communication device 122 is configured to fit inside ofthe torch insulator 118 while accommodating all other components of thetorch insulator 118 described above as well the protective layers aroundthe communication device 122, which adds to its bulk. For example, thecommunication device 122 can be designed to be long, thin and/orflexible to better fit within the torch insulator 118.

During operation, the plasma arc torch 100 can cause up to 100 Celsiusin ambient temperature, which leaves little margin for operatingtemperature rise. Therefore, in some embodiments, the communicationdevice 122 is designed to generate minimal operating temperature. Forexample, the communication device 122 can have a low circuit powervoltage, a low multi-point-control-unit (MCU) clock frequency, a lowoperational duty cycle and/or a sleep mode for while not performing tominimize heat generation.

In some embodiments, the torch communication circuit, which includes thecommunication device 122 and the signal device 160, is off axis from thecentral longitudinal axis A of the plasma arc torch 10. This offsetallows the communication circuitry to be away from the region of thetorch that defines plasma process performance. In general, the areawhere the communication circuit is placed is not vulnerable to variationin plasma process designs, which allows design freedom for the plasmaprocess and stability for the communication circuitry performance. Insome embodiments, to reduce unwanted coupling between the torchcommunication circuit and nearby metal components, the size of theantenna coil 814 is minimized (e.g., reduced coil diameter) and/or theRFID power is minimized to reduce the size of the resulting RFID field.In general, adjacent metal components that can potentially couple withthe RFID field can be accounted for and held substantially consistent insize and proximity relative to the torch communication circuit.

In alternative embodiments, the plasma arc torch 10 does not include acommunication system that comprises, for example, the communicationdevice 122 in the torch head 102 or the signal device 106 in thecartridge 104. For example, a communication system can be absent in atorch where the cartridge 104 is connected to the torch head 102 or aquick-disconnect torch head, which in turn is connected to a torchreceptacle.

In some embodiments, as illustrated in FIGS. 2 and 10, the communicationsystem of the plasma arc torch 10 further includes a second signaldevice 162 (e.g., an RFID tag) disposed in or on the communicationdevice 122 in the torch insulator 118, such as in the antenna assembly808 of the communication device 122 close to the antenna coil 814.Alternatively, the second signal device 162 can be located in the torchhead 102 external to the communication device 122 and/or the torchinsulator 118. An optional base 164 can be used to hold the secondsignal device 162 in place. The second signal device 162 is configuredto read and/or write information about the plasma arc torch 10 (e.g.,number of arcs fired) and communicate the information to the plasmacutting system, which can then relay the information to first signaldevice 160 in the cartridge 104. Generally, the first and second signaldevices 160, 162 can transfer information back and forth between them.

c. Ohmic Contact

In another aspect, the torch insulator 118 can be configured to supportohmic contact for the purpose of controlling a relative height betweenthe torch 10 and a workpiece to facilitate torch operation. In someembodiments, the torch insulator 118 includes an ohmic contact cavity146 (shown in FIG. 8) with an opening 146 a at the proximal end 21 ofthe torch insulator 118 (shown in FIG. 3). FIG. 8 is a sectional view ofthe plasma arc torch 10 of FIG. 2 oriented to illustrate an exemplaryohmic contact path 780, according to an illustrative embodiment of thepresent invention. As shown, the ohmic contact cavity 146 of the torchinsulator 118 in the torch head 102 can be configured to retain an ohmiccontact connection 131, which is removable from the cavity 146 via theopening 146 a (shown in FIG. 3). In some embodiments, the ohmic contactcavity 146 extends partially into the torch insulator 118 along thelongitudinal axis A such that there is no corresponding opening on thedistal end 23 of the torch insulator 118.

The ohmic contact path 780 of FIG. 8 allows a controller (not shown) ofthe torch 10 to detect and sense a workpiece/plate 782 for the purposeof controlling the relative height between the torch 10 and theworkpiece/plate 782 prior to or during a torch operation. With respectto the ohmic contact path 780, when the torch head 102 is mounted duringtorch operation, an incoming pin (not shown) makes electrical contactwith the ohmic contact connection 131 to form the electrical contactpath 780. The path 780 then continues through the length of the ohmiccontact connection 131 to electrically contact the torch body 18 via aset screw 784. The path 780 travels distally over the torch body 18 andthe retaining cap 120 to reach the shield 114 of the cartridge 104. Thispath 780 allows the controller to sense the location of theworkpiece/plate 782 and adjust the relative height accordingly. In someembodiments, the shield 114 of the cartridge 104 is electricallyisolated from the nozzle 110 of the cartridge 104 to allow the ohmiccontact path 780 to travel from the torch head 102 to the shield 114 onthe outer surface of the torch 10.

In some embodiments, the ohmic contact path 780 of FIG. 8 iselectrically isolated from the pilot arc current flow path 752 and/orthe transferred arc current flow path by the use of the torch insulator118. For example, pilot arc current flow path 752 and the transferredarc current flow path can be through the torch insulator 118 while theohmic contact path 780 is mostly through the torch body 18.

d. Shield Gas

In another aspect, the torch insulator 118 can be configured to directone or more gas flows from the torch head 102 to the cartridge 104. Insome embodiments, the torch insulator 118 is configured to direct atleast one shield gas from the torch head 102 to the cartridge 104.Exemplary shield gases include air, oxygen (i.e. O₂), and argon. In someembodiments, the shield gas flow path and channels described herein arealso compatible with conducting a shield fluid, such as water, betweenthe torch head 102 and the cartridge 104. The torch insulator 118 caninclude a shield gas channel 850 extending from an opening 126 a at theproximal end 21 of the torch insulator 118 (shown in FIG. 3) to a shieldgas opening 126 b at the distal end 23 of the torch insulator 118 (shownin FIG. 4).

FIGS. 11a and b are sectional views of the plasma arc torch 10 of FIG. 2oriented to illustrate an exemplary shield gas flow path 868 from thetorch head 102 to the cartridge 104 over the shield gas channel 850(including shield gas channel segments 850 a and 850 c), according to anillustrative embodiment of the present invention. As shown, the shieldgas channel 850 can comprise several segments. A first channel segment850 a connects the opening 126 a on the proximal end 21 of the torchinsulator 118 to an internal opening 860 in or on the insulator 118. Thefirst channel segment 850 a can extend substantially parallel to thelongitudinal axis A. A second channel segment (not shown) can connectthe opening 860 with another internal opening 862 in or on the insulator118, where the second internal opening 862 is radially offset from thefirst internal opening 860. For example, the internal openings 860, 862can be radially offset by about 30 degrees to about 90 degrees. Thesecond channel segment can extend circumferentially around the torchinsulator 118 (or in a different orientation) to connect the internalopenings 860, 862. A third channel segment 850 c connects the internalopening 862 to the opening 126 b on the distal end 23 of the torchinsulator 118. The third channel segment 850 c can extend substantiallyparallel to the longitudinal axis A.

In some embodiments, upon attachment of the cartridge 104 onto the torchhead 102, a corresponding shield gas channel 864 within the cartridgeframe 112 of the cartridge 104 fluidly aligns with the shield gaschannel segment 850 c. The shield gas flow 868 can enter the cartridge104 via a proximal opening 864 a of the shield gas channel 864 in thecartridge frame 112. The shield gas channel 864 also has an opening 864b at a distal end of the cartridge frame 112 that is fluidly connectedto a gas passage 872 between the shield 114 and the nozzle 110. Thus,the shield gas channel 864 can introduce a shield gas from the torchhead 102 to the gas passage 872. In some embodiments, the cartridgeframe 112 includes one or more components in the path of the shield gaschannel 864 to adjust one or more parameters (e.g., flow pattern andrate) of the shield gas flow 868 therein. Details regarding the shieldgas channel 864, the swirling components of the cartridge frame 112 andthe shield gas flow 868 through the cartridge 104 are described below.

With respect to the shield gas flow path 868 shown in FIGS. 11a and b ,a shield gas is introduced to the torch head 102 via the shield gasopening 126 a at the proximal end 21 of the torch insulator 118. The gas868 flows distally through the shield gas channel segment 850 a to reachthe internal opening 860. The gas 868 can then flow circumferentially(or in a different orientation) around the torch insulator 118 via thesecond segment of the shield gas channel 850 to reach the internalopening 862 that is spaced relative to the internal opening 860. The gas868 flows longitudinally from the opening 862 to the opening 126 b onthe distal end 23 of the torch insulator 118 via the shield gas channelsegment 850 c to reach the cartridge 104. Upon exiting the torch head102 via the opening 126 b, the shield gas flow 868 enters the shield gaschannel 864 of the cartridge frame 112 in the cartridge 104. The gas 868flows distally through the shield gas channel 864 of the cartridge frame112 and exits from the opening 864 b of the shield gas channel 864 tothe gas passage 872 between the shield 114 and the nozzle 110 to coolthe two components. The shield gas 868 is adapted to exit the cartridge104 via the shield exit orifice 870.

e. Plasma Gas

In some embodiments, the torch insulator 118 of the torch head 102 candirect one or more plasma gases from the torch head 102 to the cartridge104. For example, the torch insulator 118 can be configured to receivemultiple sources of gas, select one of the gases or mix the gases, andintroduce the selected gas or gas mixture to the cartridge 104. FIGS.12a-c are sectional views of the plasma arc torch 10 of FIG. 2 orientedto illustrate an exemplary plasma gas flow path 900 from the torch head102 to the cartridge 104, according to an illustrative embodiment of thepresent invention.

The torch insulator 118 includes two plasma gas openings 200 a and 200 bat the proximal end 21 of the torch insulator 118, where each opening isconfigured to receive a plasma gas, such as oxygen (O₂), air, nitrogen(N₂), hydrogen-based gases (e.g., H35), F5 fuel gas, or a mixture of oneor more of these chemicals. In addition, the torch insulator 118 caninclude a cavity 202 (shown in FIGS. 12a-c ) configured to house aplasma gas valve 204. The cavity 202 is connected to an opening 202 a atthe proximal end 21 of the torch insulator 118 (shown in FIG. 3),through which the plasma gas valve 204 can be removably disposed in thecavity 202. The plasma gas valve 204 is configured to select one of thegases or mix the gases received from the plasma gas openings 200 a and200 b and introduce the resulting gas or gas mixture to the cartridge104 over a plasma gas channel 206 (shown in FIGS. 12a-c ) and via anopening 200 c on the distal end 23 of the torch insulator 118 (alsoshown in FIG. 4).

As shown in FIG. 12a , the exemplary plasma gas flow path 900 comprisesa first plasma gas flow 900 a introduced from the plasma gas opening 200a to the plasma gas valve 204 located in the cavity 202 via a connectionchannel 902. The connection channel 902 fluidly connects the opening 200a with an inlet 904 of the plasma gas valve 204 to introduce the firstplasma gas flow 902 to the valve 204. As shown in FIG. 12b , the plasmagas flow path 900 comprises a second plasma gas flow 900 b introducedfrom the plasma gas opening 200 b to the plasma gas valve 204 via aconnection channel 906. The connection channel 906 fluidly connects theopening 200 b with a second inlet 908 for introducing the second plasmagas flow 900 b to the plasma gas valve 204. As shown in FIG. 12c , theplasma gas valve 204 selects one of the gases or mixes the gases andtransmits the resulting plasma gas flow 900 c over the plasma gaschannel 206 to exit from the opening 200 c at the distal end 23 of thetorch insulator 118. The plasma gas channel 206 is adapted to extendlongitudinally along the length of the torch 10 and fluidly connect anoutlet 910 of the plasma gas valve 204 to the opening 200 c at thedistal end 23 of the torch insulator 118.

With respect to the plasma gas flow path 900 c shown in FIG. 12c , uponexiting the torch head 102 via the opening 200 c, the plasma gas flow900 c enters a corresponding plasma gas channel 912 of the cartridgeframe 112 in the cartridge 104 via an opening 912 a on a proximal end 15of the cartridge frame 112. The gas 900 c flows longitudinally throughthe plasma gas channel 912 of the cartridge frame 112 and exits from anopening 912 b at the distal end 17 of the cartridge frame 112, whichintroduces the gas to the plasma gas passage 918 between the electrode108 and the nozzle 110 of the cartridge 104. The plasma gas 900 c isadapted to flow distally through the passage 918 and exit the cartridge104 via the central nozzle exit orifice 916 and the central shield exitorifice 870. In some embodiments, the swirl ring 150 in the path of theplasma gas flow 900 c can introduce a swirling motion to the plasma gasflow 900 c. Details regarding the plasma gas channel 912, the swirl ring150, and the plasma gas flow 900 c through the cartridge 104 aredescribed below.

In some embodiments, the shield gas flow 868 and the plasma gas flow 900are fluidly isolated from each other in both the torch head 102 and thecartridge 104 such that these gases do not cross paths or share the samechannels. For example, the plasma gas channel 206 and the shield gaschannel 850 are fluidly isolated from each other. In some embodiments,the torch insulator 118 of the torch head 102 is configured to controlgas flows through the torch 10 by directing the shield gas flow 868 andthe plasma gas flow 900 to the appropriate channels within the cartridgeframe 112 for distribution to the appropriate gas passageways in thecartridge 104 (e.g., the passage 872 between the nozzle 110 and theshield 114 for the shield gas flow 868 and the passage 918 between theelectrode 108 and the nozzle 110 for the plasma gas flow 900 c).

f. Liquid Coolant Flow

In another aspect, the torch insulator 118 can be configured to direct asequence of liquid coolant flow for circulation between the torch head102 to the cartridge 104. Exemplary liquid coolant includes water,propylene glycol, ethylene glycol, or any number of commerciallyavailable coolants specially designed for plasma cutting systems. Asshown in FIG. 3, the torch insulator 118 can include a coolant opening128 a at the proximal end 21 of the torch insulator 118 for introducinga liquid coolant to the torch head 102.

FIGS. 13a and b are sectional views of the plasma arc torch 10 of FIG. 2oriented to illustrate an exemplary liquid coolant flow path 950 thatcirculates between the torch head 102 and the cartridge 104 in a seriesof flow segments, according to an illustrative embodiment of the presentinvention. Along the liquid coolant flow path 950 of FIG. 13a , a liquidcoolant is first introduced to the torch head 102 via the opening 128 aat the proximal end 21 of the torch insulator 118. The coolant 950 flowsfrom the opening 128 a to the cathode block 606 within the torchinsulator 118 over a connection channel 952 and enters the cathode bock606 via at least one inlet of the cathode block 606. FIGS. 14a and b areexemplary profile and proximal views of the cathode block 606 of thetorch head 102, respectively, according to an illustrative embodiment ofthe present invention. As shown in FIG. 14b , the cathode block 606 caninclude a first set of three liquid inlets 620 a-c dispersed around aninner circumference of the cathode block 606. In other embodiments, moreor fewer inlets are defined. The connection channel 952 fluidly connectsthe torch insulator opening 128 a to the first set of liquid inlets 620a-c to conduct the coolant into the cathode block 606. The liquid inlets620 a-c of the cathode block 606 can further conduct the liquid coolantinto the opening 745 at the proximal end 740 of the coolant tube 116that can be physically attached to the cathode block 606 as describedabove. In some embodiments, the connections between the inlets 620 a-cand the opening 745 at the proximal end of the coolant tube 116 arecrisscrossed (e.g., for spacing saving purpose) to deliver the coolantfrom the cathode block 606 to the coolant tube 116.

Once in the coolant tube 116, the coolant flow path 950 continues onlongitudinally toward the distal end 742 of the coolant tube 116. Thecoolant flow 950 exits from the coolant tube 116 via the distal opening746 of the coolant tube 116 and enters into a cavity 954 defined by theinner surface of the electrode 108 of the cartridge 104, therebysubstantially cooling the electrode 108. Hence, the initial coolant flowpath 950 is substantially confined within the main channel 132 of thetorch insulator 118 (which receives at least a portion of the cathode130 and the coolant tube 116) and a corresponding main channel 1020 ofthe cartridge frame 112 (which connects to the cavity 954 of theelectrode 108). As guided by the wall of the cavity 954, the coolantflow 950 reverses direction and continues on proximally in the mainchannels 1020, 132, along the outer surface of the coolant tube 116.This reverse flow also substantially cools the Louvertac band 704surrounding an exterior portion of the distal end 742 of the coolanttube 116.

The coolant flow 950 continues toward the cathode block 606 of the torchhead 102. The coolant flow 950 can enter the cathode block 606 via thedistal opening 622 of the cathode block 606 (shown in FIG. 14a ). Onceinside of the cathode block 606, the coolant 950 flows radially outwardover an exit channel 624 of the cathode 130. The exist channel 624fluidly connects the cathode 606 to a first coolant channel 958 of thetorch insulator 118 that extends longitudinally along the length of thetorch head 102 to again conduct the coolant flow 950 from the torch head102 into the cartridge 104. Specifically, the first coolant channel 958fluidly connects the exit channel 624 to a first liquid coolant opening960 a on the distal end 23 of the torch insulator 118 (also shown inFIG. 4). The first coolant channel 958 conducts the coolant flow 950from the cathode 130 to the cartridge 104 via the opening 960 a of thetorch insulator 118 and introduces the coolant flow 950 into an opening962 a on the proximal end 15 of the cartridge frame 112, where theproximal opening 962 a is connected to a corresponding first coolantchannel 962 of the cartridge frame 112 in the cartridge 104.

The coolant 950 flows distally through the cartridge frame 112 over thefirst coolant channel 962 to reach an opening 962 b at the distal end 17of the cartridge frame 112, which fluidly connects the first coolantchannel 962 in the cartridge frame 112 to a nozzle opening 966associated with the nozzle 110. Specifically, the nozzle 110 can becoupled to an outer nozzle component 111 (such as a nozzle jacket for anon-vented nozzle or a nozzle liner for a vented nozzle) and the opening966 can be on the outer nozzle component 111 such that it can introducethe coolant flow from the distal coolant channel opening 962 b to anozzle coolant flow chamber 965 between an exterior surface the nozzle110 and an interior surface of the outer nozzle component 111. As thecoolant flow 950 is conducted distally through the nozzle coolant flowchamber 965 via the nozzle opening 966, it substantially cools thenozzle 110 and the outer nozzle component 111. Upon reaching a distaltip of the nozzle 110, the coolant flow 950 can swirl around at least aportion of a circumference of the nozzle 110 via a circumferentialchannel (not shown) disposed on the external surface of the nozzle 110.The coolant flow 950 can return proximally on a different side of thenozzle 110 within the flow chamber 965 and toward another opening 967 onthe outer nozzle component 111. The second nozzle opening 967 is in turnfluidly connected to a second coolant channel 968 in the cartridge frame112. Specifically, the second coolant channel 968 interfaces with thesecond opening 967 of the outer nozzle component 111 at an opening 968 bat the distal end 17 of the cartridge frame 112. The second coolantchannel 968 of the cartridge frame 112 is adapted to conduct the liquidcoolant flow 950 away from the nozzle coolant flow chamber 965 and intoa corresponding second coolant channel 970 of the torch insulator 118 inthe torch head 102 via a a second liquid coolant channel opening 968 aon the proximal end 15 of the cartridge frame 112 and a second liquidcoolant channel opening 960 b at the distal end 23 of the torchinsulator 118 (also shown in FIG. 4). As the coolant flow 950 travelsproximally through the torch insulator 118 within the second coolantchannel 970 of the torch head 102, the coolant flow encounters aninternal opening 972 of the second coolant channel 970 in the torchinsulator 118. That is, the second coolant channel 970 connects theinternal opening 972 with the opening 960 b on the distal end 23 of thetorch insulator 118.

As illustrated in FIG. 13b , the internal opening 972 of the secondcoolant channel 970 can be fluidly connected to an internal opening 974of a third coolant channel 976 of the torch insulator 118 via adistribution channel (not shown) extending circumferentially around thetorch insulator 118. The second coolant channel 970 and the thirdcoolant channel 976 can be radially offset from each other at about 30degrees to about 90 degrees (e.g., 70 degrees). The distribution channelthus connects the internal openings 972, 974 to deliver the coolant flow950 from the second coolant channel 970 to the third coolant channel976. Within the third coolant channel 976, the coolant 950 flowsdistally toward a third coolant channel opening 960 c on the distal end23 of the torch insulator 118 (also shown in FIG. 4) to again enter thecartridge 104. Specifically, upon exiting the third coolant channel 976of the torch insulator 118 of the torch head 102 via the opening 960 c,the coolant flow 950 is adapted to enter the cartridge 104 via acorresponding third coolant channel opening 978 a on the proximal end 15of the cartridge frame 112 that is connected to a third coolant channel978 of the cartridge frame 112 to continue the distal flow toward theshield 114 in the cartridge 104. The coolant flow 950 exits the thirdcoolant channel 978 via an opening 978 b at the distal end 17 of thecartridge frame 112 to enter a circumferential shield coolant flowregion 1222 defined between an outer side surface of the cartridge frame112 and a corresponding inner surface of the shield 114. The coolantflow 950 can travel circumferentially around the shield coolant flowregion 1222, thereby cooling the shield 114. Following thecircumferential shield coolant flow region 1222, the coolant flow 950can return to the cartridge frame 112 on a different side of the flowregion 1222 by entering an opening 982 b at the distal end 17 of thecartridge frame 112. The opening 982 b, which is in fluid communicationwith the shield coolant flow region 1222, is connected to a fourthcoolant channel 982 of the cartridge frame 112. The coolant flow 950then travels proximally in the fourth coolant channel 982, exits thefourth coolant channel 982 via an opening 982 a at the proximal end 15of the cartridge frame 112, and flows into the torch head 102. Thecoolant flow 950 enters the torch head 102 via a fourth coolant channelopening 960 d at the distal end 23 of the torch insulator 118 (alsoshown in FIG. 4). The opening 960 d at the distal end 23 of the torchinsulator 118 is fluidly connected to a fourth coolant channel 984 ofthe torch insulator 118 configured to deliver the coolant flow 950 fromthe cartridge 104 to an internal opening 986 in the torch insulator 118,which is fluidly connected to the cathode block 606.

As shown in FIGS. 14a and b , the cathode block 606 comprises a secondset of one or more liquid inlets 626 extending from an exterior surfaceto an interior surface of the cathode block 606. In some embodiments,the cathode block 606 includes a second set of three liquid inlets 626a-c dispersed around an outer circumference of the cathode block 606. Inother embodiments, more or fewer inlets are defined. Shown with respectto FIG. 13b , a connection channel 988 fluidly connects the internalopening 986 of the fourth coolant channel 984 of the torch insulator 118to the second set of liquid inlets 626 a-c to conduct the coolant 950from the fourth coolant channel 984 into the cathode block 606. In someembodiments, the connections between the second set of inlets 626 a-cand the internal opening 986 are crisscrossed (e.g., for space savingpurpose) to deliver the coolant from the fourth coolant channel 984 tothe cathode block 606 in a swirling fashion. Once inside of the cathodeblock 606, the coolant flow 950 continues on proximally to exit thetorch insulator 118 via the cathode tube 604 and the cathode fitting 602in that order.

In some embodiments of the torch insulator 118, the first coolantchannel 958 and the second coolant channel 970 can be radially offsetfrom each other at about 30 degrees to 90 degrees (e.g., about 90degrees). The third coolant channel 976 and the fourth coolant channel984 can be radially offset from each other at about 30 degrees to 90degrees (e.g., about 90 degrees). In some embodiments of the cartridgeframe 112, the first coolant channel 962 and the second coolant channel968 can be radially offset from each other by the same degree as theoffset between the first coolant channel 958 and the second coolantchannel 970 of the torch insulator 118 (e.g., about 90 degrees). Thethird coolant channel 978 and the fourth coolant channel 982 can beradially offset from each other by the same degree as the offset betweenthe third coolant channel 976 and the fourth coolant channel 984 of thetorch insulator 118 (e.g., about 90 degrees). In some embodiments of theplasma arc torch 10, the second coolant channels 970, 968 are radiallyoffset from the third coolant channels 976, 978 by about 30 degrees toabout 90 degrees (e.g., 70 degrees).

In general, the torch insulator 118 of the torch head 102, incollaboration with the cartridge frame 112 of the cartridge 104, isconfigured to control distribution of a coolant flow 950 in and out ofthe torch head 102 and the cartridge 104 to various components of thecartridge tip, as described above with respect to FIGS. 13a and b . Forexample, the torch insulator 118 and the cartridge frame 112 can directthe coolant flow 950 in the following sequence: (i) from the cathode 600to the coolant tube 116 and reverse in the main channel 132 of the torchinsulator 118 and the main channel 1020 of the cartridge frame 112 tocool the electrode 108, where each of the main channels 132, 1020 actsas both a supply and return channel; (ii) from the first coolant channel958 of the torch insulator 118 (i.e. a supply channel), to the firstcoolant channel 962 of the cartridge 104 (i.e., a supply channel), tothe second coolant channel 968 of the cartridge 104 (i.e., a returnchannel) and to the second coolant channel 970 of the torch insulator118 (i.e., a return channel) to cool the nozzle 110; (iii) from thethird coolant channel 976 of the torch insulator 118 (i.e., a supplychannel), to the third coolant channel 978 of the cartridge 104 (i.e., asupply channel), to the four coolant channel 982 of the cartridge 104(i.e., a return channel) and to the fourth coolant channel 984 of thetorch insulator 118 (i.e., a return channel) to cool the shield 114. Inalternative embodiments, the coolant flow 950 comprises only one of thethree sets of the supply and return channels to cool one cartridge tipcomponent. In alternative embodiments, the coolant flow 950 comprisestwo of the three sets of the supply and return channels to cool twocartridge tip components.

Even though the coolant flow path 950 of FIGS. 13a and b is illustratedin a sequence that cools the electrode 108, followed by the nozzle 110,and then the shield 114 of the cartridge tip, other cooling sequencesare equally applicable. For example, a different sequence can includecooling of the shield 114, followed by the nozzle 110 and then theelectrode 108. Yet another sequence can include cooling of the nozzle110, followed by the shield 114 and then the electrode 108. In someembodiments, any order for cooling these three components of thecartridge tip is contemplated by the present invention.

In some embodiments, the shield gas flow path 868, the plasma gas flowpath 900 and the coolant flow path 950 are fluidly isolated from eachother in both the torch head 102 and the cartridge 104 such that thesefluids do not cross paths nor share the same channels. In someembodiments, the shield gas flow path 868, the plasma gas flow path 900and the coolant flow path 950 are predefined based on locking of thetorch head 102 with the cartridge 104 in a predetermined orientation.This locking feature will be described below in detail. In someembodiments of the torch insulator 118, one or more of the coolantchannels 968, 970, 976, 984, the plasma gas channel 206 and the shieldgas channel 850 are non-concentric with respect to the centrallongitudinal axis A. One or more of the pilot arc connection cavity 148,the communication device cavity 144 and the plasma gas valve cavity 202are non-concentric with respect to the central longitudinal axis A. Insome embodiments of the torch insulator 118 (shown in FIG. 3), one ormore of the opening 202 a for receiving the plasma gas valve 204, theplasma gas openings 200 a, 200 b, the cavity opening 148 a for receivingthe pilot arc connection 123, the liquid coolant opening 128 a, thecavity opening 146 a for receiving the ohmic connection 131, the shieldgas opening 126 a, the cavity opening 144 a for receiving thecommunication device 122, and the main channel opening 132 a aredisposed on an end face of the proximal end 21 of the torch insulator118, where the end face can be substantially planar. These openings,with the exception of the main channel opening 132 a, can be disposednon-concentrically on the proximal end face with respect to the centrallongitudinal axis A. In some embodiments of the torch insulator 118(shown in FIG. 4), one or more of the plasma gas opening 200 c, theliquid coolant openings 960 a-d and the shield gas opening 126 b, themain channel opening 132 b are disposed on an end face of the distal end23 of the torch insulator 118, where the end face can be substantiallyplanar. These openings, with the exception of the main channel opening132 a, can be disposed non-concentrically on the distal end face withrespect to the central longitudinal axis A. In the context of thepresent invention, “non-concentric” means that the applicable channel,cavity or opening is offset relative to the longitudinal axis A. In someembodiments, each non-concentric channel, cavity or opening is orientednon-symmetrically with respect to the longitudinal axis A.

In some embodiments, the main channel opening 132 a at the proximal end21 of the torch insulator 118, the main channel 132, and the mainchannel opening 132 b at the distal end 23 of the torch insulator 118are centrally located and disposed concentrically with respect to thecentral longitudinal axis A. As described above, the main channel 132 isconfigured to provide at least one of (i) a pilot arc or transferred arccurrent or (ii) at least a portion of the liquid coolant flow 950 fromthe torch head to the cartridge.

Interface Between the Torch Head and the Cartridge

With reference to FIG. 4, the distal end 23 of the torch insulator 118can further include a clocking feature 220 (e.g. a pin) configured tosecure the torch insulator 118 with the cartridge frame 112 in apredetermined radial orientation upon engagement between the torch head102 and cartridge 104. FIG. 15 is a view of the proximal end 15 of thecartridge frame 112, according to an illustrative embodiment of thepresent invention. The proximal end 15 of the cartridge frame 112 caninclude a clocking feature (e.g., a pin cavity) 1002 that can interactwith the corresponding clocking feature 220 on the distal end 23 of thetorch insulator 118 to form at least a section of the interface 106(shown in FIG. 2) between the torch head 102 and the cartridge 104. Suchan interface 106 allows alignment of various electrical, liquid coolant,and gas channels between the torch head 102 and the cartridge 104,thereby maintaining the predefined electrical, liquid coolant and gasflow paths described above with reference to FIGS. 7, 8 and 11 a-13 b.In some embodiments, the end face of the distal end 23 of the torchinsulator 118 is substantially planar. The end face of the proximal end15 of the cartridge frame 112 can also be substantially planar such thatthe interface 106 between them is substantially planar.

With respect to the continuity of coolant flow between the torch head102 and the cartridge 104, upon clocking of the torch insulator 118 withthe cartridge frame 112 in the predetermined radial orientation, thefirst liquid coolant channel opening 960 a on the distal end 23 of thetorch insulator 118 (shown in FIGS. 4 and 13 a) is aligned with thefirst coolant channel opening 962 a at the proximal end 15 of thecartridge frame 112 (shown in FIGS. 13a and 15) to fluidly connect thefirst liquid coolant channel 958 of the torch insulator 118 with thefirst liquid coolant channel 962 of the cartridge frame 112 (shown inFIG. 13a ). In the same predetermined radial orientation, the secondliquid coolant channel opening 960 b of the torch insulator 118 (shownin FIGS. 4 and 13 a) is aligned with the second coolant channel opening968 a at the proximal end 15 of the cartridge frame 112 (shown in FIGS.13a and 15) to fluidly connect the second coolant channel 970 of thetorch insulator 118 with the second coolant channel 968 of the cartridgeframe 112 (shown in FIG. 13a ). In the same predetermined radialorientation, the third liquid coolant channel opening 960 c of the torchinsulator 118 (shown in FIGS. 4 and 13 b) is aligned with the thirdcoolant channel opening 978 a at the proximal end 15 of the cartridgeframe 112 (shown in FIGS. 13b and 15) to fluidly connect the thirdcoolant channel 976 of the coolant insulator 118 with the third coolantchannel 978 of the cartridge frame 112 (shown in FIG. 13b ). In the samepredetermined radial orientation, the fourth liquid coolant channelopening 960 d of the torch insulator 118 (shown in FIGS. 4 and 13 b) isaligned with the fourth coolant channel opening 982 a of the cartridgeframe 112 (shown in FIGS. 13b and 15) to fluidly connect the fourthcoolant channel 984 of the coolant insulator 118 with the fourth coolantchannel 982 of the cartridge frame 112 (shown in FIG. 13b ).

With respect to the continuity of gas flows between the torch head 102and the cartridge 104, in the predetermined radial orientation, theshield gas opening 126 b on the distal end 23 of the torch insulator 118(shown in FIGS. 4 and 11 b) is aligned with the shield gas opening 864 aat the proximal end 15 of the cartridge frame 112 (shown in FIGS. 11band 15) to fluidly connect the third shield gas channel segment 850 c ofthe torch insulator 118 with the shield gas channel 864 of the cartridgeframe 112 (shown in FIG. 11b ). In the same predetermined radialorientation, the plasma gas opening 200 c on the distal end 23 of thetorch insulator 118 (shown in FIGS. 4 and 12 c) is aligned with theplasma gas proximal opening 912 a at the proximal end 15 of thecartridge frame 112 (shown in FIGS. 12c and 15) to fluidly connect theplasma gas channel 206 of the torch insulator 118 with the plasma gaschannel 912 of the cartridge frame 118 (shown in FIG. 12c ).

With respect to data communication between the torch head 102 and thecartridge 104, in the predetermined radial orientation enabled by theclocking features 220, 1002, the reader device 122 is rotationallyaligned with the signal device 160. For example, the antenna coil 814embedded in the torch insulator 118 can map to an area 230 at the distalend 23 of the torch insulator 118 (shown in FIG. 4) with a center 232that substantially aligns with a center 1018 of an area 1016 at theproximal end 15 of the cartridge frame 112 (shown in FIG. 15), whichmaps to the signal device 160 embedded in the cartridge 104. Suchrotational alignment between the centers 232, 1018 reduces communicationinterference between the reader device 122 and the signal device 160.

FIG. 31 is a portion of the plasma arc torch 10 of FIG. 2 illustratingexemplary locations of the communication device 122 and the signaldevice 160 once the torch head 102 and the cartridge 104 are in thepredetermined radial orientation relative to each other, according to anillustrative embodiment of the present invention. In some embodiments,in the aligned position, a distance 816 between the longitudinal andradial center of the antenna coil 814 and the longitudinal and radialcenter of the signal device 160 is less than a distance between thelongitudinal and radial center of the signal device 160 and any adjacentmetallic material disposed in the torch head 102 or the cartridge 104.In some embodiments, the RFID field generated by the antenna coil 814 istoroidal in shape around the perimeter of the disc-shaped RFID tag 160.A cross section of the toroidal field at any point is a circle. Toprevent interference, the distance between the RFID tag 160 and thereader device 122 along an x axis (measured at the center point of thecircular cross-section of the field) is smaller or closer than thedistance between the RFID tag 160 to any adjacent metal along the Yaxis. Thus, as the RFID field moves in a circular path around thetoroidal shape, the field is configured such that it does not encounterany metal before it encounters the RFID tag 160. In some embodiments, inthe aligned position, the signal device 160 and the reader device 122are oriented such that a straight-line axis extends through a centerlineof the signal device 160 and a centerline of the reader device 122. Insome embodiments, the antenna coil 814 of the reader device 122 isoriented substantially parallel to the signal device 160. In someembodiments, the antenna coil 814 and the RFID tag 160 communicate at afrequency of about 13.5 MHz.

With respect to the continuity of electrical connections between thetorch head 102 and the cartridge 104 as shown in FIG. 2, uponinterfacing the torch insulator 118 with the cartridge frame 112, thedistal opening 132 b of the main channel 132 of the torch insulator 118is adapted to align with the opening 1020 a at the proximal end 15 ofthe cartridge frame 112 to connect to the main channel 1020 of thecartridge frame 112. Thus, the distal end 742 of the coolant tube 116 isadapted to be inserted into the main channel 1020 of the cartridge frame112 via the opening 1020 a. An opening 1020 b of the main channel 1020at the distal end 17 of the cartridge frame 112 is connected to thecavity 954 of the electrode 108 such that the coolant tube 116 extendsthrough the opening 1020 b and into the cavity 954. As explained above,pilot arc current and/or transferred arc current from the power supplycan be routed from the cathode 130 of the torch head 102 to the coolanttube 116, both of which are affixed to the torch insulator 118, and tothe electrode 108 of the cartridge 104 via the inner surface of theelectrode cavity 954. The current-carrying coolant tube 116 thusenergizes the interior surface of the electrode 108. In someembodiments, one or more Louvertac bands 702, 704 on either or both ends740, 742 of the coolant tube 116 are used to facilitate conduction ofelectricity from the power supply to the inner surface of the electrode108. The use of at least the Louvertac band 704 at the distal end 742 ofthe coolant tube 116 radially aligns/centers the electrode 108 relativeto the coolant tube 116, but does not affix the electrode 108 to anyparticular radial orientation. For example, during assembly, an operatorcan apply an axial force to push the electrode 108 proximally againstthe coolant tube 116 until the Louvertac band 704 at the distal end 742of the coolant tube 116 is fully seated within the cavity 954 of theelectrode 108 and is covered by most of the cavity 954. The Louvertacband 704 of the coolant tube 116 thus allows the electrode 108 to beaxially pushed on or pulled off during engagement or disengagement,respectively, without the use of threading (or other clocking movement),thereby enabling the use of a tool-free and/or threadless electrode 108.

The simple push-on/pull-off feature is also compatible with theengagement between the clocking feature 220 of the torch insulator 118and the clocking feature 1002 of the cartridge frame 112 to form theinterface 106. That is, the coupling between the torch head 102 and thecartridge 104 can be governed by the locking features 220, 1002 withoutthe need to account for any threading or other clocking requirementbetween the electrode 108 and the coolant tube 116. In general, allowingthe coolant tube 116 and the Louvertac band 704 to carry the pilotarc/transferred arc current to the cartridge 104 separates (i) thephysical interface between the torch insulator 118 and the cartridgeframe 112 from (ii) the electrical connection between the cathode130/coolant tube 116 and the electrode 108. This separation is adaptedto maximize design space and simplify torch assembly. In addition, therelatively straight axial installation and removal of the coolant tube116 (and thus the torch head 102) from the electrode 108 (and thus thecartridge 104) promotes quicker consumable replacement and installation.Further, due to the placement of the Louvertac band 704 in relation tothe coolant tube 116 (e.g., on an exterior surface of the coolant tube116), the Louvertac band 704 can be easily inspected and readilyserviced. In alternative embodiments, instead of using the Louvertacband 704, other current-carrying and/or retaining features can be used,such as thread attachments, interference fits, etc.

In some embodiments, because the cutting current is carried from thepower supply to the electrode 108 by the coolant tube 116, the electrode108 does not need to be in directly electrical or physical contact withthe torch head 102 for current transfer purposes. In some embodiments,the electrode 108 is electrically isolated from the torch head 102 bythe cathode block electrode tube 252, which connects the electrode 108to the cathode 130 and the coolant tube 116. The cathode block electrodetube 252 can be made of a non-conductive material such as plastic. Inanother aspect, the electrode 108 is shorter than an electrode that isused to receive a current directly from the cathode. In this case,because the electrode 108 no longer physically or electrically contactsthe cathode 130, the electrode 108 can be shorter, such as more than 25%shorter, than a direct-contact electrode.

Upon axial insertion of the coolant tube 116 into the cavity 954 of theelectrode 108 and radial clocking of the torch insulator 118 with thecartridge frame 112 (e.g., via insertion of the clocking pin 220 of thetorch insulator 118 into the clocking pin cavity/receptacle 1002 of thecartridge frame 112), the cartridge 104 can be retained against thetorch head 102 using the retaining cap 120 (shown in FIG. 1). Otherengagement methods between the torch head 102 and the cartridge 104 arepossible, including threading, snap fit, interference fit, etc. FIG. 16is a sectional view of an exemplary design of the retaining cap 120 ofFIG. 1 used to secure the cartridge 104 and the torch head 102 to eachother, according to an illustrative embodiment of the present invention.The retaining cap 120 includes a body 764, a proximal end 760 and adistal end 762 extending along the longitudinal axis A. The proximal end760 of the retaining cap body 764 includes an engagement feature 766(e.g., groove, thread or step) circumferentially disposed on an internalsurface to capture the torch head 102 against the retaining cap body764. Similarly, the distal end 762 of the retaining cap body 764includes an engagement feature 768 (e.g., groove, thread or step)disposed on an internal surface to capture the cartridge 104 against theretaining cap body 764. Thus, upon clocking of the cartridge 104 withthe torch head 102, the retaining cap 120 can securely andcircumferentially surround an external surface of the torch head 102 atthe distal end 22 of the torch head 102 and an external surface of thecartridge 104 at the proximal end 14 of the cartridge 104. In someembodiments, the torch head 102 and/or the cartridge do not rotate withrespect to the retaining cap 120. In this case, an operator can slidethe retaining cap 120 over the cartridge 104 and/or the torch head 102to lock the parts without using any rotational movement. In someembodiments, the retaining cap 120 is provided as a part of the torchhead 102. In some embodiments, the retaining cap 120 is provided as apart of the cartridge 104. In some embodiments, the retaining cap 120 isprovided as a distinct component separate from the cartridge 104 ortorch head 102.

Cartridge

FIG. 17 is a sectional view of the cartridge 104 of FIG. 1, where thecartridge 104 is a non-vented cartridge, according to an illustrativeembodiment of the present invention. As described above, the cartridge104 can generally include the cartridge frame 112 coupled to thecartridge tip that includes the electrode 108, the nozzle 110, which isa non-vented nozzle attached to a nozzle jacket 111, and the shield 114.The cartridge frame 112 is adapted to form an interface between thecartridge tip and the torch head 102, thereby connecting the cartridgetip to the torch head 102. The various components of the cartridge 104,including the cartridge frame 112, the electrode 108, the nozzle 110,the nozzle jacket 111 and the shield 114, can be concentrically disposedabout the longitudinal axis A of the plasma arc torch 10. In someembodiments, the cartridge 104 includes multiple retaining features thatallow the components of the cartridge tip to align with and engage toone or more channels in the cartridge frame 112 such that these channelscan conduct liquid and gas from the torch head 102, through thecartridge frame 112, and to the desired components in the cartridge tip.In some embodiments, the proximal end 14 of the cartridge 104, includingthe proximal end 15 of the cartridge frame 112, is substantially planar.

In general, the various components of the cartridge tip can be secured,either directly or indirectly, to the cartridge frame 112 whileachieving axial alignment and radial alignment (i.e., centering) withrespect to the cartridge frame 112. The electrode 108 can be secured tothe cartridge frame 112 with at least a portion of the electrode 108disposed in the central channel 1020 of the cartridge frame 112. In someembodiments, the electrode 108 is secured to the cartridge frame 112 viathe swirl ring 150 that surrounds at least a portion of the main channel1020. Specifically, an outer diameter of the electrode 108 can besecured to an inner diameter of the swirl ring 150 such that at least aproximal portion of the electrode 108 is inserted into a distal portionof the swirl ring 150. If the swirl ring 150 is electrically conductive,the swirl ring 150 can be secured to the electrode 108 via the electrodeinsulator 754. As shown, the electrode 108 includes an outer retainingfeature 1066 (e.g., one or more steps of varying diameter of theelectrode 108) on an exterior surface configured to matingly engage aninner retaining feature 1068 (e.g., one or more complementary steps orprotrusions) on an interior surface of the electrode insulator 754 toprevent axial movement of the electrode 108 and the electrode insulator754 relative to each other. The mating between the retaining features1066, 1068 can be one of snap fit, press fit or interference fit. Theresulting interface 1067 between the electrode 108 and the electrodeinsulator 754 also radially aligns/centers the two components. In turn,the electrode insulator 754 includes an outer retaining feature 1056(e.g., a step of varying diameter of the electrode insulator 754) on anexterior surface to matingly engage an inner retaining feature 1054(e.g., a complementary step or protrusion) on an interior surface of theswirl ring 150 to prevent axial movement of the electrode insulator 754and the swirl ring 150 relative to each other. The mating between theretaining feature 1054, 1056 can be one of snap fit, press fit orinterference fit. The resulting interface 1055 between the electrodeinsulator 754 and the swirl ring 150 also radially aligns/centers thetwo components. If the swirl ring 150 is substantially non-conductive,the swirl ring 150 can be directly secured to the electrode 108 withoutthe use of the electrode insulator 754. In some embodiments, an outerdiameter of the swirl ring 150 is matingly engaged to an inner diameterof the cartridge frame 112 to couple the electrode 108 to the cartridgeframe 112. For example, the swirl ring 150 can be secured to thecartridge frame 112 by matingly engaging an outer retaining feature 1052(e.g., a step of varying diameter of the swirl ring 150) on an exteriorsurface with an inner retaining feature 1058 (e.g., a complementary stepor protrusion) on an interior surface of the cartridge frame 112 toprevent axial movement of the swirl ring 150 and the cartridge frame 112relative to each other. The mating between the retaining features 1052,1058 can be one of snap fit, press fit or interference fit. Theresulting interface 1053 between the swirl ring 150 and the cartridgeframe 112 also radially aligns/centers the two components.

The nozzle 110 and the nozzle jacket 111 can be engaged between theswirl ring 150 and the cartridge frame 112. In some embodiments, anouter diameter of the swirl ring 150 is engaged to an inner diameter ofthe nozzle 110. The swirl ring 150 can be secured to the nozzle 110 bymatingly engaging an outer retaining feature 1050 (e.g., one or moresteps of varying diameter of the swirl ring 150) on an exterior surfacewith an inner retaining feature 1060 (e.g., a complementary step orprotrusion) on an interior surface of the nozzle 110 to prevent axialmovement of the swirl ring 150 and the nozzle 110 relative to eachother. The mating between the retaining features 1050, 1060 can be oneof snap fit, press fit or interference fit. The resulting interface 1051between the swirl ring 150 and the nozzle 110 also radiallyaligns/centers the two components. In some embodiments, an outerdiameter of the nozzle 110 is secured to an inner diameter of thecartridge frame 112. The nozzle 110 can be secured to the cartridgeframe 112 by matingly engaging at least one outer retaining feature 1070(e.g., one or more steps of varying diameter of the nozzle 110) on anexterior surface to at least one inner retaining feature 1072 (one ormore complementary steps or protrusions) on an interior surface of thecartridge frame 112 to prevent axial movement of the nozzle 110 and thecartridge frame 112 relative to each other. The mating between theretaining features 1070, 1072 can be one of snap fit, press fit orinterference fit. The resulting interface 1071 between the nozzle 110and the cartridge frame 112 also radially aligns/centers the twocomponents.

The shield 114 can be coupled to an outer surface the cartridge frame112. For example, an outer diameter of the cartridge frame 112 issecured to an inner diameter of the shield 114 by matingly engaging anouter retaining feature 1062 (e.g., a step of varying diameter of thecartridge frame 112) on an exterior surface of the cartridge frame 112with an inner retaining feature 1064 (e.g., a complementary step orprotrusion) on an interior surface of the shield 114 to prevent axialmovement of the cartridge frame 112 and the shield 114 relative to eachother. The mating between the retaining features 1062, 1064 can be oneof snap fit, press fit or interference fit. The resulting interface 1063between the cartridge frame 112 and the shield 114 also radiallyaligns/centers the two components. In addition, the cartridge frame 112can include an indentation 1065 on an exterior surface configured toreceive a distal portion of the shield 114 via crimping, thereby furthersecuring and aligning the shield 114 to the cartridge frame 112.

In some embodiments, the retaining features 1050-1072 described abovecan mate with their corresponding retaining features through one of snapfit, press fit, interference fit, crimping, frictional fitting, gluing,cementing or welding. In some embodiments, the retaining features1050-1072 include one or more sealing o-rings or gaskets, made ofhardening epoxy or rubber for example. In some embodiments, theretaining features 1050-1072 allow the nozzle 110, the jacket 111, theshield 114 and/or the electrode 108 of the cartridge tip to align withand engage to one or more channels in the cartridge frame 112 such thatthese channels can conduct liquid and/or gas from the torch head 102,through the cartridge frame 112, and to the desired components in thecartridge tip. The liquid and gas connections between the cartridgeframe 112 and the cartridge tip is described below in detail.

FIG. 18 is an exemplary design of the cartridge frame 112 of thecartridge 104 of FIG. 17, according to an illustrative embodiment of thepresent invention. The cartridge frame 112 includes a generallycylindrical insulator body 1100 disposed between the torch head 102 andthe cartridge tip. More specifically, the insulator body 1100 includesan inner region 1106, an outer side surface 1108, an inner side surface1110 surrounding and forming the main channel 1020, the proximal end 15having an end face 1102, and the distal end 17 having an end face 1104.The proximal end 15 of the cartridge frame 112, which is described abovewith respect to FIG. 15, comprises the central opening 1020 a forreceiving an electrical current and/or the coolant flow 950 from acoolant tube 116 of the torch head 102, a plasma gas opening 912 a forreceiving the plasma gas flow 900 c from the torch insulator 118, ashield gas opening 864 a for receiving the shield gas flow 868 from thetorch insulator 118 and four liquid coolant openings 968 a, 978 a, 962 aand 982 a for conducting the liquid coolant flow 950 in and out of thecartridge 104. In some embodiments, these openings are disposed on theend face 1102 of the proximal end 15 of the insulator body 1100. In someembodiments, the end face 1102 is substantially coplanar with theproximal end 14 of the cartridge 104. In general, these openings areconfigured to be in electrical and/or fluid communication with theircorresponding openings on the distal end 23 of the torch insulator 118once the torch head 102 is aligned with and connected to the cartridge104 in a predetermined orientation via the locking feature 1002 of thecartridge frame 112 and the corresponding locking feature 220 of thetorch insulator 118.

Electrical Connections in the Cartridge

In some embodiments, the electrode 108 is aligned with and connected tothe main channel 1020 disposed in the insulator body 1100 of thecartridge frame 112. The channel 1020 can be centrally disposed in theinsulator body 110 with the central longitudinal axis A extendingtherethrough to connect the opening 1020 a on the end face 1102 of theproximal end 15 of the cartridge frame 112 to the opening 1020 b on theend face 1104 of the distal end 17 of the cartridge frame 112. Thedistal opening 1020 b is in turn connected to and aligned with thecavity 954 of the electrode 108 (shown in FIG. 2). Such an electrodeinterface allows the coolant tube 116 to be inserted into the mainchannel 1020 to pass an electrical current (i.e., a pilot arc ortransferred arc current) from the cathode 130 of the torch head 102 tothe inner surface of the electrode 108, as described above. In such acase, the electrode 108 can be electrically isolated from the cathode130, as described above. In alternative embodiments, the electrode 108is electrically connected to the cathode 130 to receive a currentdirectly from the cathode 130. In some embodiments, the same electrodeinterface (i.e., between the electrode 108 and the torch head 102 viathe main channel 1020 of the cartridge frame 112) can allow the torchhead 102 to introduce a liquid coolant to the electrode 118 from insideof the coolant tube 116. This liquid coolant conduction feature of themain channel 1020 of the cartridge frame 112 is explained in detailbelow.

FIG. 19 is an exemplary design of the electrode 108 of the cartridge 104of FIG. 17, according to an illustrative embodiment of the presentinvention. An emissive insert 1200 can be disposed in the distal end1202 of the electrode 108 so that an emission surface is exposed. Theinsert 1200 can be made of hafnium or other materials that possesssuitable physical characteristics, including corrosion resistance and ahigh thermionic emissivity. Forging, impact extrusion, or cold formingcan be used to initially form the electrode 108 prior to finishmachining the component. The proximal end 1204 of the electrode 108 canbe disposed in and aligned with the main channel 1020 of the cartridgeframe 112 via the distal opening 1020 b of the cartridge frame 112. Theelectrode 108 can be connected to the cartridge frame 112 using at leastthe swirl ring 150 and the electrode insulator 754. In some embodiments,the electrode 108 does not include any threads for connection to theelectrode insulator 754 or the swirl ring 150. As explained above, sucha connection can be made through one of press fit, interference fit,crimping or snap fit. In some embodiments, the electrode 108 is shorterthan an electrode that is used to receive an electrical current directlyfrom the cathode 130 (i.e., without using the coolant tube 116). Inthese cases, because the electrode 108 does not need to physically orelectrically contact the cathode 130, the electrode 108 can be shorter,such as more than 25% shorter, than a direct-contact electrode. In someembodiments, the electrode 108 includes an o-ring groove 1205 at theproximal end 1204, where the o-ring groove 1205 is configured to housean o-ring that can be used to seal a plasma chamber/plenum 109cooperatively defined by the electrode 108 and the nozzle 110. Suchsealing prevents the plasma gas flow 900 c from traveling between theelectrode 108 and the electrode insulator 754 (shown in FIG. 17).

Shield Gas Connections in the Cartridge

In some embodiments, the shield gas passage 872 formed between theshield 114 and the nozzle jacket 111 is aligned with the shield gaschannel 864 disposed in the insulator body 1100 of the cartridge frame112 (shown in FIGS. 11a and b ). The shield gas channel 864 (shown inFIGS. 11a and b ) can extend substantially parallel to the longitudinalaxis A in the inner region 1106 of the insulator body 1100, but offsetfrom the central longitudinal axis A (i.e., non-concentric with respectto the longitudinal axis A). The shield gas channel 864 connects theopening 864 a on the end face 1102 at the proximal end 15 of thecartridge frame 112 to the opening 864 b at the distal end 17 of thecartridge frame 112. In some embodiments, the opening 864 b is disposedon the end face 1104 of the distal end 17 of the cartridge frame 112. Inalternative embodiments, the opening 864 b of the shield gas channel864, which is distal to the opening 864 a along the longitudinal axis A,is disposed on the outer side surface 1108 or the inner side surface1110 of the cartridge frame body 1100 (i.e., the channel 864 does notextend through the entire length of the body 1100 in the longitudinaldirection). The opening 864 b is in turn fluidly connected to the shieldgas passage 872, which allows the shield gas flow 868 to pass from thetorch head 102, through the cartridge frame 112 of the cartridge 104,and into the shield gas passage 872 (shown in FIGS. 11a and b ). In someembodiments, the shield gas channel 864 can be configured to provide ametering function to the shield gas flow 868 therein. For example, thediameter of the shield gas channel 864 can vary over the length of thechannel to provide the metering function. The diameter of the shield gaschannel 864 at the distal end 17 of the cartridge frame 112 can be abouthalf of the diameter of the shield gas channel 864 at the proximal end15 of the cartridge frame 112 to reduce the flow rate of the shield gasflow 868.

In some embodiments, the cartridge frame 112 includes one morecomponents in the path of the shield gas channel 864 to adjust one ormore properties of the shield gas flow 868 therein. For example, thecartridge frame 112 can include an adjustment component, such as atwo-piece component comprising a baffle 1112 and a shield swirl ring1114. As shown in FIG. 17, the baffle 1112 and the shield swirl ring1114 are circumferentially disposed within the insulator body 1100 ofthe cartridge frame 112 at its distal end 17 and the two components arein the path of the shield gas channel opening 864 b such that theyadjust certain flow parameters and introduce a swirling motion to theshield gas flow 868 as it exits the cartridge frame 112 and into theshield gas passage 872. The use of these two separate components 1112,1114 provide manufacturing and assembly advantages as an operator canuse different combinations of baffles and shield swirl rings to developdifferent types of shield gas flows.

FIG. 20 is a cross-sectional view of the baffle 1112 and the shieldswirl ring 1114 attached to the cartridge frame 112 of the cartridge 104of FIG. 17, according to an illustrative embodiment of the presentinvention. In some embodiments, at least one of the baffle 1112 or theshield swirl ring 1114 is made of a non-conductive material, such asTorlon™. In some embodiments, at least one of the baffle 1112 or theshield swirl ring 1114 is made of a conductive material. The baffle 1112and the shield swirl ring 1114 can be individually manufactured throughmolding, stamping or die casting.

As shown, the baffle 1112 is situated proximal to the shield swirl ring1114 such that when the shield gas flow 868 travels distally, it isfirst regulated by the baffle 1112 and then by the shield swirl ring1114. In other embodiments, the position of the baffle 1112 and theshield swirl ring 1114 are reversed. The baffle 1112 can becircumferentially disposed within the insulator body 1100 of thecartridge frame 112, such as within a cavity 1116 at the distal end 17of the insulator body 1100. The baffle 1112 can be secured to the cavity1116 by one of interference fit or press fit. The baffle 1112 includes alongitudinal portion 1118 and a radial portion 1120 that is connected tothe longitudinal portion 1118 at an angle such that the radial portion1120 covers a portion of the width 1122 of the cavity 1116, but leaves aradial clearance 1124 between an outer diameter of the radial portion1120 and an inner surface of the cavity 1116. The shield gas flow 868within the shield gas channel 864 is adapted to be dispersed by thebaffle 1112 to flow evenly around its outer diameter through the radialclearance 1124 and into the swirl ring 1114. The radial clearance 1124is shaped and dimensioned to adjust at least one parameter of the shieldgas flow 868. For example, the radial clearance 1124 can adjust a flowrate and/or fluid pressure of the shield gas flow 868. In someembodiments, increasing the size of the radial clearance 1124 increasesthe flow rate of the shield gas flow 868, in which case the plasma arctorch system can adjust accordingly to maintain a constant pressure. Insome embodiments, increasing the size of the radial clearance 1124decreases the gas pressure, in which case the plasma arc torch systemcan adjust accordingly to maintain a constant flow rate.

The shield swirl ring 1114 can be inserted into at least a portion ofthe cavity 1116 by at least one of interference fit or press fit suchthat it is distal in relation to the baffle 1112. FIG. 21 is across-sectional view of the shield swirl ring 1114, according to anillustrative embodiment of the present invention. The shield swirl ring1114 can define a first set of ports 1126 around a first circumferenceof the swirl ring 1114 and a second set of ports 1128 around a secondcircumference of the swirl ring 1114, where each port connects aninterior surface of the cartridge frame 112 to an exterior surface ofthe cartridge frame 112. The first set of ports 1126 are offset fromtheir respective ones of the second set of ports 1128. Such an offsetimparts a swirling motion to the shield gas flow 868 therethrough.Therefore, the combination of the baffle 1112 and the shield swirl ring1114 can adjust parameters of the shield gas flow 868 as it travelsdistally through the shield gas channel 864 to the shield gas passage872. Generally, the shield gas flow 868 in the plasma arc torch 10 isconfigurable by varying the size of the clearance 1124 of the baffleand/or the sizes of the first and second sets of ports 1126, 1128 in theshield swirl ring 1114.

Plasma Gas Connections in the Cartridge

In some embodiments, the plasma gas passage 918 formed between theelectrode 108 and the nozzle 110 is aligned with the plasma gas channel912 disposed in the insulator body 1100 of the cartridge frame 112(shown in FIGS. 12a-c ). The plasma gas channel 912 (shown in FIGS.12a-c ) can extend substantially parallel to the longitudinal axis A inthe inner region 1106 of the insulator body 1100, but offset from thelongitudinal axis A (i.e., non-concentric with respect to thelongitudinal axis A). The plasma gas channel 912 connects the opening912 a on the proximal surface 1102 at the proximal end 15 of thecartridge frame 112 to the opening 912 b. In some embodiments, theopening 912 b of the plasma gas channel 912, which is distal to theopening 912 a along the longitudinal axis A, is disposed on the innerside surface 1110 of the cartridge frame body 1100 and in fluidcommunication with the central channel 1020. Thus, in thisconfiguration, the plasma gas channel 912 does not extend over theentire length of the cartridge frame body 1100 in the longitudinaldirection.

FIG. 22 is a perspective view of the cartridge frame 112 illustratingvarious channel openings, including the opening 912 b of the plasma gaschannel 912, according to an illustrative embodiment of the presentinvention. As shown, the opening 912 b is on the inner side surface 1110in a central region of the cartridge frame 112, and the opening 912 b isfluidly connected to the central channel 1020. In alternativeembodiments, the plasma gas channel 912 extends over the entire lengthof the cartridge frame 112 with the opening 912 b located on the distalend face 1104 of the cartridge frame insulator body 1100. The opening912 b is fluidly connected to the plasma gas passage 918. Such aconnection allows the plasma gas flow 900 c to pass from the torch head102, through the cartridge frame 112, and into the plasma gas passage918, which merges into the central main channel 1020, before the plasmagas flow 900 c exits the torch 10 via the central nozzle exit orifice916 and the central shield exit orifice 870 (shown in FIGS. 12a-c ).

In some embodiments, the cartridge frame 112 includes one morecomponents in the path of the plasma gas channel 912 configured toadjust one or more properties of the plasma gas flow 900 c therein. Forexample, the cartridge frame 112 can include the swirl ring 150circumferentially situated between the electrode insulator 754 and thenozzle 110 around the main channel 1020. The swirl ring 150 can bealigned with the distal plasma gas channel opening 912 b such that theswirl ring 150 can introduce a swirling motion to the plasma gas flow900 c as it exits the plasma gas channel 912 via the opening 912 b onthe inner side surface 1110 of the cartridge frame 112 and into theplasma gas passage 918.

FIG. 23 is an exemplary design of the swirl ring 150 of the cartridge104 of FIG. 17, according to an illustrative embodiment of the presentinvention. As shown, the swirl ring 150 can be defined by asubstantially hollow, elongated body 1170 having a proximal end 1174 anda distal end 1172 along the central longitudinal axis A of the plasmaarc torch 10. In some embodiments, the hollow body 1170 of the swirlring 102 at the distal end 1172 is dimensioned to receive a least aportion of the electrode 104 either directly or indirectly via theelectrode insulator 754. In some embodiments, the swirl ring 150includes a set of radially spaced gas flow openings 1176 disposed aboutthe distal end 1172 of the elongated body 1170, such as around acircumference of its distal end 1172. Each gas flow opening 1176 canextend from an interior surface to an exterior surface of the elongatedbody 1170 and is oriented to impart a tangential velocity component tothe plasma gas flow 900 c traveling in the gas passage 918 between theelectrode 108 and the nozzle 110, thereby causing the gas flow 900 c toswirl. This swirl creates a vortex that constricts the plasma arc andstabilizes the position of the arc on the insert 1200 of the electrode108.

Coolant Connections in the Cartridge

In some embodiments, as described above, a component of the cartridgetip (e.g., the electrode 108, the nozzle 110 or the shield 114) can bealigned with at least one cooling channel (e.g., channel 1002, 962 or978) and at least one coolant return channel (channel 1002, 968 or 982)in the insulator body 1100 of the cartridge frame 112 to receive aliquid coolant flow from the torch head 102 and return at least aportion of the fluid flow to the torch head 102, respectively. Each ofthe cooling channels and the return channels, with the exception of themain channel 1002, can be non-concentric with respect to the centrallongitudinal axis A and asymmetric about the longitudinal axis A. Insome embodiments, with the exception of the main channel 1002, none ofthe cooling and returning channels are overlapping. That is, with theexception of the main channel 1002, each of the cooling and returningchannels is either a liquid inlet channel or a liquid outlet channel.

In some embodiments, the central channel 1020 extends through theinsulator body 1100 of the cartridge frame 112 to connect its opening1020 a on the end face 1102 at the proximal end 15 of the cartridgeframe 112 to its opening 1020 b at the distal end 17 of the cartridgeframe 112. The proximal opening 1020 a is aligned with and connected tothe main channel opening 132 b of the torch insulator 118. The distalopening 1020 b is aligned with and connected to the cavity 954 of theelectrode 108, which allows the coolant flow 950 to pass from the torchhead 102, through the cartridge frame 112 while inside of the coolanttube 116, and into the cavity 954 of the electrode 108 (shown in FIGS.13a and b ). This connection also allows the coolant flow 950 to impingeon the inner surface of the distal end of the cavity 954 such that thecoolant flow 950 can reverse direction and travel proximally through themain channel 1020 along an outer surface of the coolant tube 116 towardthe torch head 102 (shown in FIGS. 13a and b ). This reverse coolantflow over the exterior surface of the coolant tube 116 alsosubstantially cools the Louvertac band 704 attached to the distal end742 of the coolant tube 116. In some embodiments, the reverse coolantflow can travel through the longitudinal channels 744 on the exteriorsurface of the coolant tube 116 beneath the Louvertac band 704, therebylimiting a pressure drop between the coolant tube 116 and the electrode108.

In some embodiments, the nozzle opening 966, which can be formed on thenozzle jacket 111, is aligned with the first coolant channel 962disposed in the insulator body 1100 of the cartridge frame 112 (shown inFIGS. 13a and b ). The nozzle opening 966 allows the coolant flow 950from the first coolant channel 962 to enter the nozzle coolant flowchamber 965 between an exterior surface of the nozzle 110 and aninterior surface of the nozzle jacket 111. The first coolant channel 962(shown in FIGS. 13a and b ) can extend substantially parallel to thelongitudinal axis A in the inner region 1106 of the insulator body 1100,but offset from the longitudinal axis A (i.e., non-concentric withrespect to the longitudinal axis A). The first coolant channel 962 canconnect the opening 962 a on the end face 1102 at the proximal end 15 ofthe cartridge frame 112 to the opening 962 b of the cartridge frame 112,which is distal to the opening 962 a along the longitudinal axis A. Theopening 962 b is in turn fluidly connected to the nozzle opening 966,which allows the coolant flow 950 to travel distally from the torch head102, through the cartridge frame 112 of the cartridge 104, and into thenozzle coolant flow chamber 965 (shown in FIGS. 13a and b ).

In some embodiments, the opening 962 b of the first coolant channel 962is disposed on the inner side surface 1110 of the cartridge frame body1100 and in fluid communication with the central channel 1020. Thus, inthis configuration, the first coolant channel 962 does not extend overthe entire length of the cartridge frame body 1100 in the longitudinaldirection. The opening 962 b of the first coolant channel 962 isillustrated in FIG. 22. As shown, the opening 962 b is on the inner sidesurface 1110 toward the distal end 17 of the cartridge frame 112, andthe opening 962 b is fluidly connected to the central channel 1020. Inalternative embodiments, the first coolant channel 962 extends over theentire length of the cartridge frame 112 with the opening 962 b locatedon the distal end face 1104 of the cartridge frame insulator body 1100.The opening 962 b is fluidly connected to the nozzle opening 966 in thenozzle jacket 111. Such a connection allows the liquid coolant flow 950to pass from the torch head 102, through the cartridge frame 112, andinto the nozzle coolant flow chamber 965 between the nozzle 110 and thenozzle jacket 111 to cool the two nozzle components.

As explained above, the nozzle opening 966 is configured to be alignedwith the first coolant channel 962 of the cartridge frame 112 such thatthe coolant flow 950 can be introduced into the nozzle coolant flowchamber 965 from the first coolant channel 962 via the nozzle opening966. The nozzle opening 966 can be in fluid communication with thesecond nozzle opening 967 on the nozzle jacket 111, where the twocoolant openings 966, 967 are radially offset from each other (i.e., ondifferent sides of the nozzle 110). The coolant flow 950 can enter thenozzle coolant flow chamber 965 via the nozzle opening 966, flowproximally through the flow chamber 965, return distally on a differentside of the chamber 965, and exit the chamber 965 via the second opening967. In some embodiments, the second opening 967 is aligned with andconnected to the second coolant channel 968 disposed in the cartridgeframe 112 (shown in FIGS. 13a and b ). The second coolant channel 968can extend substantially parallel to the longitudinal axis A within theinner region 1106 of the insulator body 1100, but offset from thelongitudinal axis A (i.e., non-concentric with respect to thelongitudinal axis A). The second coolant channel 968 connects theopening 968 a on the end face 1102 at the proximal end 15 of thecartridge frame 112 to the opening 968 b at the distal end 17 of thecartridge frame 112, which is in turn connected to the second nozzleopening 967. Such a connection allows the coolant flow 950 to travelproximally from the nozzle coolant chamber 965, through the cartridgeframe 112 of the cartridge 104, and into the torch head 102 (shown inFIGS. 13a and b ). In some embodiments, the opening 968 b of the secondcoolant channel 968, which is distal to the opening 968 a along thelongitudinal axis A, is disposed on the inner side surface 1110 of thecartridge frame body 1100. Thus the first and second coolant channels962, 968, in cooperation with the nozzle openings 966, 967 allow thecoolant flow 950 to cool the nozzle 110 and the nozzle jacket 111 viathe nozzle coolant flow chamber 965.

FIGS. 24a and b are exterior views of the non-vented nozzle 110 and thenozzle jacket 111 of FIG. 17, respectively, according to an illustrativeembodiment of the present invention. The non-vented nozzle 110 includesa proximal end/portion 1206, a middle portion 1208, and a distalend/portion 1210 along the longitudinal axis A of the torch 10. Thedistal end 1210 of the nozzle 108 includes the centrally-located nozzleexit orifice 916 for introducing a plasma arc, such as an ionized gasjet, to a workpiece (not shown) to be cut. The nozzle jacket 111includes a substantially hollow body 1212 defining a proximal end 1214and a distal end 1216 along the longitudinal axis A. The nozzle 110 isadapted to be inserted into the hollow body 1212 of the nozzle jacket111 such that the distal end 1210 of the nozzle 108 extends through theopening of the distal end 1216 of the nozzle jacket 111.

In some embodiments, the nozzle jacket 111 includes the nozzle openings966, 967 at its proximal end 1214, where each opening connects anexterior surface to an interior surface of the nozzle jacket body 1212.The openings 966, 967 can be oriented on substantially opposite sides ofnozzle jacket 111 (e.g., about 180 degrees from each other). In someembodiments, the exterior surface of the middle portion 1208 of thenozzle 111 and a corresponding interior surface of the nozzle jacket 111cooperatively define the nozzle coolant flow chamber 965. The flowchamber 965 can be located approximately in the middle of the nozzle 110and the nozzle jacket 111 along the longitudinal axis A and/or at theirwidest radial sections. In some embodiments, the distal portion 1210 ofthe nozzle 110 includes a circumferential flow channel 1218 about thenozzle 110 (i.e., a flow channel extending about 360 degrees around thenozzle 110) that is located through the opening at the distal end 1216of the nozzle jacket 111. The circumferential channel 1218 permits acoolant to flow over the exterior surface of the tip of the nozzle 110,thereby promoting convective cooling of the nozzle tip during torchoperation and reducing stagnation of the flowing liquid. Thecircumferential flow channel 1218 can be defined at least in part by acurvilinear surface of the nozzle 110.

In operation, the cooling liquid flow 950 can enter the flow chamber 965via the opening 966 on one side of the nozzle jacket 111. The coolingliquid flow 950 can travel distally toward the circumferential flowchannel 1218 in a longitudinal direction over one side of the flowchamber 965. Upon reaching the circumferential flow channel 1218, thecoolant flow 950 can swirl about the nozzle tip and return proximally onthe other side of the nozzle 110 substantially opposite (e.g., about 180degrees) of the distal flow. The return flow 950 can exit from thenozzle coolant flow chamber 965 to the cartridge frame 112 via theopening 967.

In some embodiments, an internal surface of the shield 114 is in fluidcommunication with the third coolant channel 978 disposed in theinsulator body 1100 of the cartridge frame 112 (shown in FIGS. 13a and b). The third coolant channel 978 can extend substantially parallel tothe longitudinal axis A in the inner region 1106 of the insulator body1100, but offset from the longitudinal axis A (i.e., non-concentric withrespect to the longitudinal axis A). The third coolant channel 978 canconnect the opening 978 a on the end face 1102 at the proximal end 15 ofthe cartridge frame 112 to the opening 978 b in the cartridge frame 112,which is distal to the opening 978 a along the longitudinal axis A. Insome embodiments, the opening 978 b of the third coolant channel 978 isdisposed on the outer side surface 1108 of the cartridge frame body1100. Thus, in this configuration, the third coolant channel 978 doesnot extend over the entire length of the cartridge frame body 1100 inthe longitudinal direction. The opening 978 b of the third coolantchannel 978 is illustrated in FIG. 22. As shown, the opening 978 b is onthe outer side surface 1108 in the middle portion of the cartridge frame112. In alternative embodiments, the third coolant channel 978 extendsover the entire length of the cartridge frame 112 with the opening 978 blocated on the distal end face 1104 of the cartridge frame insulatorbody 1100. The opening 978 b can be fluidly exposed to an inner surfaceof the shield 114, which allows the coolant flow 950 to travel distallyfrom the torch head 102, through the cartridge frame 112 of thecartridge 104, and into the shield 114 (shown in FIGS. 13a and b ).

In some embodiments, as shown in FIG. 22, the outer side surface 1108 ofthe middle section of the cartridge frame 112 defines a circumferentialflow channel 1220 about the cartridge frame 112 (i.e., a flow channelextending about 360 degrees around the cartridge frame 112). Thecircumferential channel 1220 is fluidly connected to the opening 978 bof the third coolant channel 978. The circumferential channel 1220, incooperation with an inner circumference of the shield 114, forms ashield coolant flow region 1222 (shown in FIG. 13b ) that permits thecoolant flow 950 to flow therethrough, thereby cooling the innercircumference of the shield 114. In some embodiments, thecircumferential channel 1220 is in fluid communication with the opening982 b of the fourth coolant channel 982 of the cartridge frame 112 thatcan also be located on the outer side surface 1108 of the cartridgeframe 112. The opening 982 b is distal to the opening 982 a along thelongitudinal axis A. The openings 978 b, 982 b can be radially offsetrelative to each other, such as by 180 degrees so they are on oppositesides of the cartridge frame 112. The fourth coolant channel 982 canextend substantially parallel to the longitudinal axis A, but offsetfrom the longitudinal axis A (i.e., non-concentric with respect to thelongitudinal axis A). The fourth coolant channel 982 is adapted toconnect the opening 982 a on the end face 1102 at the proximal end 15 ofthe cartridge frame 112 to the opening 982 b.

In operation, the coolant flow 950 can travel distally to the shield 114via the opening 978 b of the third coolant channel 978. Upon enteringthe shield coolant flow region 1222 (i.e., defined by thecircumferential flow channel 1220 on the outer side surface 1108 of thecartridge frame 112 and the corresponding inner circumference of theshield 114), the coolant flow 950 can swirl about the shield coolantflow region 1222 and return proximally on the other side of the shieldcoolant flow region 1222 substantially opposite (e.g., about 180degrees) of the distal flow. The return flow 950 can exit the shieldcoolant flow region 1222 to the cartridge frame 112 via the opening 982b of the fourth coolant channel 982.

FIG. 25 is a cross sectional view of the shield 114 of the cartridge 104of FIG. 17, according to an illustrative embodiment of the presentinvention. The shield 114 comprises a substantially hollow bodyincluding a centrally located shield exit orifice 870 and, optionally,one or more gas vent holes (not shown) extending from an interiorsurface to an exterior surface of the shield 114. The shield 114 can becold formed or stamped using copper.

In general, with reference to the proximal end 15 of the cartridge frame112, the first coolant channel opening 962 a can function as a coolantinlet to the nozzle 110, the second coolant channel opening 968 a canfunction as a coolant outlet from the nozzle 110, the third coolantchannel opening 978 a can function as a coolant inlet to the shield 114,and the fourth coolant channel opening 982 a can function as a coolantoutlet from the shield 114. In some embodiments, when the torch head 102is coupled to the cartridge 104, the second coolant channel opening 968a, which functions as a coolant outlet from the nozzle 110 is fluidlyconnected to the third coolant channel opening 978 a, which functions asa coolant inlet to the shield 114. Specifically, a distribution channelin the torch insulator 118, which connects the internal openings 972,974 of the torch insulator 118 as described above with reference toFIGS. 13a and b , can direct the coolant flow 950 from the secondcoolant channel 968 to the third coolant channel 978 to cool both thenozzle and the shield.

In some embodiments, one or more of the liquid coolant channel openings962 a, 968 a, 978 a, 982 a, the plasma gas channel opening 912 a, theshield gas channel opening 864 a, and the main channel opening 1020 aare disposed on the end face 1102 of the proximal end 21 of the torchinsulator 118, where the end face can be substantially planar. Theseopenings, with the exception of the main channel opening 1020 a, can bedisposed non-concentrically on the proximal end face 1102 with respectto the central longitudinal axis A. In some embodiments, one or more ofthe coolant channels 962, 968, 978, 982, the plasma gas channel 912, andthe shield gas channel 864 of the cartridge frame 112 are non-concentricwith respect to the central longitudinal axis A.

RFID Communication in the Cartridge

In some embodiments, the cartridge frame 112 forms a communicationinterface (e.g., an RFID communication interface) between the torch head102 and the cartridge tip. With reference to FIG. 17, the insulator body1100 of the cartridge frame includes an RFID mounting feature 1230formed on or in cartridge frame 112 adjacent to the end face 1102 of theproximal end 15 of the cartridge frame 112. For example, the mountingfeature 1230 can be a cavity disposed in the cartridge frame body 1110from the end face 1102. The RFID mounting feature 1230 (e.g., a cavity)can be disposed in the inner region 1106 of the cartridge frame 112 andcan be located/oriented in a non-concentric manner relative to thecentral longitudinal axis A.

The signal device 160 can be disposed in or on the mounting feature 1230to transmit information about the cartridge 104 (e.g., about theelectrode 108, the nozzle 110, the shield 114 and/or the cartridge frame112 itself) to an adjacent reader device, such as to the communicationdevice 122 in the torch insulator 118 when the torch head 102 is coupledto the cartridge 104. For example, the signal device 160 can be embeddedin the cavity 1230 and surrounded by the insulator material of thecartridge frame body 1100. The signal device 160 can be an electricallywritable and/or readable RFID tag. Exemplary information encoded on thesignal device 160 can include generic or fixed information, such as acomponent's name, trademark, manufacturer, serial number, and/or type.In some embodiments, the encoded information is unique to the component,such as metal composition of the component, weight of the component,date, time and/or location of when the component was manufactured, etc.Information encoded to the signal device 160 can also specify operatingparameters and/or data about the component that is independent of adetectable physical characteristic of the component. The signal device160 can be an RFID tag or card, bar code label or tag, integratedcircuit (IC) plate, or the like.

In some embodiments, the end face 1102 of the proximal end 15 of thecartridge frame 112 is substantially planar. In this configuration, ifthe cartridge 104 is not coupled to the torch head 102, an operator canplace a reader, such as an RFID reader installed on a handheld device,flat against the substantially planar end face 1102 to interrogate thesignal device 160 and extract information stored on the signal device160. Hence, the cartridge frame 112 can be configured such that thesignal device 160 mounted in or on the cartridge frame 112 is readablefrom inside of the plasma arc torch 10 (e.g., by the communicationdevice 122 of the torch head 102) or outside of the plasma arc torch 10(e.g., by an external reader).

In another aspect of the present invention, the torch head 102 can becoupled to a cartridge that includes a vented nozzle, in which case thetorch head 102 still provides substantially the same functions as itprovides for the non-vented cartridge 104. FIG. 26 is an exemplaryvented cartridge 1300 compatible with the torch head 102 of the plasmaarc torch 10 of FIG. 1, according to an illustrative embodiment of thepresent invention. The cartridge frame 1302 of the vented cartridge 1300can be substantially the same in configuration and/or materialcomposition as the cartridge frame 112 of the non-vented cartridge 104such that the cartridge frame 1302 maintains the same interface betweenthe torch head 102 and the components of the cartridge tip, including anelectrode 1308, a vented nozzle 1310 coupled to a nozzle liner 1311, anda shield 1314. For example, the electrode 1308 can be substantially thesame as the electrode 108 of the non-vented cartridge 104, and theelectrode 1308 can be affixed to the cartridge frame 1302 in the samemanner as the electrode 108 to the cartridge frame 112. The shield 1314can be substantially the same as the shield 114 of the non-ventedcartridge 104, and the shield 1314 can be be affixed to the cartridgeframe 1302 in the same way as the shield 114 to the cartridge frame 112.

The nozzle liner 1311 can be disposed in and affixed to an interiorsurface of the vented nozzle 1310. Each of the nozzle liner 1311 and thenozzle 1310 can be directly affixed to the cartridge frame 1302 suchthat the nozzle liner 1311 and the nozzle 1310 are axially and radiallyaligned to the cartridge frame 1302. In some embodiments, as illustratedin FIG. 26, a radial distance 1360 between an interior surface of aswirl ring 1316 of the vented cartridge 1300 and an exterior surface ofthe electrode 1308 is about 0.08 inches. In some embodiments, theclosest breakdown gap distance 1362 between an exterior surface of theelectrode 108 and an interior surface of the nozzle liner 1311 is about0.05 inches.

FIGS. 27a and b are exterior views of the nozzle liner 1311 and thevented nozzle 1310 of the cartridge 1300 of FIG. 26, respectively,according to an illustrative embodiment of the present invention. Asshown in FIG. 27b , the vented nozzle 1310 includes a substantiallyhollow body having a proximal end/portion 1326 and a distal end/portion1328 along the longitudinal axis A of the torch 10. The distal end 1328of the nozzle 1310 includes a centrally-located nozzle exit orifice 1332for introducing a plasma arc, such as an ionized gas jet, to a workpiece(not shown) to be cut. In some embodiments, the nozzle 1310 includes acircumferential coolant channel 1339 about an exterior surface of thenozzle 1310 (i.e., a flow channel extending about 360 degrees around thenozzle 110) that is located at the proximal end 1326. Thecircumferential channel 1339 permits a liquid coolant to flow over theexterior surface of the nozzle 1310 in a swirling pattern, therebypromoting convective cooling and reducing stagnation of the flowingliquid.

As shown in FIG. 27a , the nozzle liner 1311 includes a substantiallyhollow body defining a proximal end 1334 and a distal end 1336 along thelongitudinal axis A. The nozzle liner 1311 includes a central opening1338 at the distal end 1336 and one or more plasma gas channels 1337oriented longitudinally on an outer surface of the liner 1311 around thecentral opening 1338. In some embodiments, the nozzle liner 1311includes one or more vent holes 1346 at its proximal end 1334 forallowing a vented plasma gas flow to travel from an interior surface toan exterior surface of the nozzle liner 1311. The vent holes 1346 can besuitably metered to control one or more flow parameters. The nozzleliner 1311 is adapted to be disposed in the hollow body of the nozzle1310 from an opening at the distal portion 1326 of the nozzle 1310. Thenozzle liner 1311 can be radially aligned/centered with respect to thenozzle 1310. The central opening 1338 can be in fluid communication withthe nozzle exit orifice 1332 once the nozzle liner 1311 is disposed intothe nozzle 1310. The distal end 1334 of the nozzle liner 1311 can beexposed such that the vent holes 1346 are unobstructed by the nozzle1310.

In some embodiments, the shield gas flow through the vented cartridge1300 is substantially the same as the shield gas flow 868 through thenon-vented cartridge 104. In some embodiments, the plasma gas flowthrough the cartridge frame 1302 is the same as the plasma gas flow 900c through the cartridge frame 112. The plasma gas flow path after itexits from the cartridge frame 112 is illustrated in FIG. 26.Substantially the same as the plasma gas flow path 900 b of thecartridge frame 112, the swirl ring 1316 can be configured to introducea swirling motion to the plasma gas flow 1340 as it flows distally toexit the cartridge frame 1302. The plasma gas flow 1340 then travelsdistally between the electrode 1308 and the nozzle liner 1311 to reach aplenum 1342 cooperatively defined by the electrode 1308, the nozzleliner 1311 and the nozzle 1310. The plasma gas flow 1340 can exit theplasma arc torch 10 by travelling through the plenum 1342, the centralopening 1338 of the nozzle liner 1311, the central nozzle exit orifice1332 and a central shield exit orifice 1344. A small portion 1341 of theplasma gas flow 1340 in the plenum 1342 can be vented distally via theone or more plasma gas channels 1337 between the exterior surface of theliner 1311 and the interior surface of the nozzle 1310.

As the plasma gas flow 1341 travels distally between the liner 1311 andthe nozzle 1310, it reaches the proximal end 1324 of the nozzle liner1311 and can exit the nozzle liner 1311 via the vent hole 1346 at theproximal end 1324, which connects an interior surface of the nozzleliner body 1311 to an exterior surface of the nozzle liner body 1311.The vent hole 1346 is adapted to be in fluid communication with a ventchannel 1348 that is radially oriented in the body of the cartridgeframe 1302 to connect an inner side surface of the cartridge frame 1302and an outer side surface of the cartridge frame 1302, which is in turnexposed to atmosphere. In some embodiments, a similar vent channel canbe constructed in the insulator body 1100 of the cartridge frame 112 forthe non-vented cartridge 112 such that the same cartridge frame isusable in both the vented and the non-vented cartridge design. Thus, thedistal plasma gas flow 1341 can exit the nozzle 1310 via the vent hole1346 to enter the vent channel 1348 disposed in the body of thecartridge frame 1302. The distal plasma gas flow 1341 can be vented toatmosphere by following the vent channel 1348 from the inner sidesurface to the outer side surface of the cartridge frame 1302. In someembodiments, if a retaining cap 120 is used to connect the cartridgeframe 1302 to the torch head 102, a vent hole disposed in the body ofthe retaining cap 120 can align with the vent channel 1348 of thecartridge frame to allow the distal plasma gas flow 1341 to escape fromthe torch 10. In general, by allowing the plasma gas flow 1341 to bevented from the cartridge 1300 instead of the torch head 102, the ozonein the plasma gas flow 1341 would not otherwise destroy the torch 10since the torch head 102 is a more durable component that can berepeatedly used while the cartridge 1300 is a consumable component thatcan be regularly replaced (e.g., about every 2-20 hours of operation,such as about every 8 hours of operation) or replaced after each use.

In some embodiments, the coolant flow through the cartridge frame 1302is substantially the same as the liquid coolant flow 950 through thecartridge frame 112. In the vented cartridge 1300, the coolant flow cancool the electrode 1308 and the shield 1314 in substantially the samemanner as the coolant flow 950 for the non-vented cartridge 104 usingsame coolant channels and passages/flow regions. For example, coolingthe electrode 1308 in the vented cartridge 1300 can be the same ascooling the electrode 108 of the non-vented cartridge 104 by using themain coolant channel 1002 connected to the cavity 954 of the electrode108. As another example, cooling the shield 1314 in the vented cartridge1300 can be the same as cooling the shield 114 of the non-ventedcartridge 104 by using the third and fourth coolant channels 978, 982connected to the shield coolant flow region 1222 of the shield 114.

For cooling the vented nozzle 1310 in the vented cartridge 1300, thecoolant flow through the cartridge frame 1302 is substantially the sameas the liquid coolant flow 950 through the cartridge frame 112 over thefirst and second coolant channels 962, 968. The coolant flow pathtowards the vented nozzle 1310 after it exits from the cartridge frame112 is illustrated in FIG. 26. As shown, the opening 962 b of the firstcoolant channel 962, which is situated on the inner side surface of thecartridge frame 1302, conducts a coolant flow 1350 from the inner regionof the cartridge frame 1302 to a central main channel 1351 (e.g., sameas the main channel 1020 of the cartridge frame 112). The coolant flow1350 can travel distally out of the cartridge 1302 over the main channel1351 and into a nozzle coolant flow region 1352 defined between thecircumferential channel 1339 on the exterior surface of the nozzle 1310and an interior surface of the shield 1314. For example, the opening 962b of first coolant channel 962 can be in fluid communication with thecircumferential channel 1339 (and the nozzle coolant flow region 1352)such that it centrally conducts the coolant flow 1350 from the cartridgeframe 1302 to the nozzle coolant flow region 1352 from one side of thenozzle 1310. The coolant flow 1350 can travel distally toward thecircumferential flow channel 1339 in a longitudinal direction over oneside of the nozzle coolant flow region 1352. Upon reaching thecircumferential flow channel 1339, the coolant flow 1350 can swirl aboutthe nozzle 1310 and return proximally on the other side of the nozzle1310 substantially opposite (e.g., about 180 degrees) of the distalflow. The circumferential flow channel 1339 can also be in fluidcommunication with the opening 968 b of the second coolant channel 968such that the return flow 1350 can exit from the nozzle coolant flowregion 1352 and enter the cartridge frame 1302 via the opening 968 b ofthe second coolant channel 968.

In some embodiments, unlike the coolant flow 950 with respect to thenon-vented nozzle 110, the coolant flow 1350 for the vented cartridge1300 does not enter a region between the liner 1311 and the ventednozzle 1310. Instead, the coolant flow 1350 flows around an exteriorcircumference of the nozzle 1310 that is spaced distally relative to theliner 1311.

Generally, the cartridge frame 112 for the non-vented cartridge 104 andthe cartridge frame 1302 for the vented cartridge 1300 can be the same.In some embodiments, the same cartridge frame can be used in differenttypes of cartridges by aligning and attaching different types ofcomponents to the cartridge frame. For example, as described above, acartridge frame of the present invention can be coupled to a vented ornon-vented nozzle to customize plasma gas venting capabilities. Asanother example, different swirl rings (e.g., the swirl ring 150 orswirl ring 1316) can be attached to the cartridge frame to customize theswirling pattern of the plasma gas flow through the cartridge. As yetanother example, different baffles (e.g., the baffle 1112) or shieldswirl rings (e.g., the shield swirl ring 1114) can be attached to thecartridge frame to customize flow properties of the shield gas flowthrough the cartridge. Thus, the cartridge frame of the presentinvention allows the consumable cartridge to be configurable andcustomizable to realize different cutting objectives.

FIG. 28 is another exemplary cartridge frame 1400 that can be suitablyconfigured to form a cartridge compatible with the torch head 102 ofFIG. 1, according to an illustrative embodiment of the presentinvention. The cartridge frame 1400 is substantially the same as thecartridge frame 112 or the cartridge frame 1302. The main difference isthe shape of the proximal end 1402 of the cartridge frame 1400, whichhas a “flower petal” configuration. All other features of the cartridgeframe 1400, including the inlet and outlet openings and channels, remainthe same as those of the cartridge frame 112. Same as the cartridgeframe 112, the cartridge frame 1400 can be made of an insulatormaterial, such as Torlon™ or polyphenylene sulfide. The “flower petal”configuration of the proximal end 1402 of the cartridge frame 1400allows the cartridge frame 1400 to be manufactured using an injectionmolding technique, which provides a faster and cheaper manufacturingapproach in comparison to traditional processes, including using lessmass, cools better and more evenly with no cavitation. In alternativeembodiments, the cartridge frame 112 or 1400 can be machined.

In some embodiments, at least one of the nozzle jacket 111 or theelectrode insulator 754 is made from a non-conductive material, such asTorlon™ or polyphenylene sulfide. At least one of the electrodes 108,1308, the insert 1200, the non-vented nozzle 110, the vented nozzle1310, the nozzle liner 1311, or the shields 114, 1314 can be made from aconductive material, such as copper or brass. The swirl rings 150, 1316can be made from a conductive material, such as zinc (e.g., Zamac 3).Each of the baffle 1112 or the shield swirl ring 1114 can be made froman insulator material or a conductive material. In some embodiments,each of the non-vented cartridge 104 or vented cartridge 1300 iscomposed of at least about 50% of plastic by volume. In someembodiments, an overall length of the cartridge 104 or 1300 along thelongitudinal axis A is about 2 inches, and the largest diameter of thecartridge 104 or 1300 along a plane perpendicular to the longitudinalaxis A is about 1.7 inches.

The electrodes 108, 1308 and the shields 114, 1314 can be manufacturedusing a cold forming, stamping or machining technique. The non-ventednozzle 110 or the vented nozzle 1310 can be manufactured using coldforming, stamping or machining with features (e.g., holes) drilled in.The swirl rings 150, 1316 can be manufactured using die casting withswirl holes drilled in, injection molding with swirl holes drilled in,or machining. The baffle 1112 can be formed using stamping, die casting,machining or molding. The shield swirl ring 1114 can be formed using diecasting, molding or machining. In general, to reduce manufacturing costand complexity, the cartridge 104 or 1300 includes little or no Vespel™,little or no lava, little or no aluminum, minimal copper usage, and/orvery few o-ring grooves. Further, the components of the cartridges 104,1300 are manufactured to minimize drilled holes.

In some embodiments, the cartridge 104 or the cartridge 1300 is designedto be non-planar in the proximal end such that the interface between thecartridge and the torch head 102 is also non planar. FIG. 29 is anexemplary vented cartridge 1450 that includes a non-planar proximal end1452, according to an illustrative embodiment of the present invention.The vented cartridge 1450 can comprise an end face 1458 and a protrudingdistal portion 1460 disposed on a cartridge frame 1454. Specifically,the protruding distal portion 1460 is a portion of the cartridge frame1454 that forms the main central channel 1456. The protruding distalportion 1460 can extend distally along the longitudinal axis A beyondthe end face 1458 of the inner region 1462 of the cartridge frame 1454.All other features/functions of the cartridge 1450 can remainsubstantially the same as the vented cartridge 1300 described above.

FIG. 30 is an exploded view of the cartridge 104 of FIG. 18, accordingto an illustrative embodiment of the present invention. To assemble thecartridge 104, the emissive insert 1200 can be first inserted into theelectrode 108 at the distal end 1202 of the electrode 108. The electrode108 can then be coupled to the electrode insulator 754 from the distalend of the electrode insulator 754. For example, the outer retainingfeatures 1066 of the electrode 108 can matingly engage the innerretaining features 1068 of the electrode 754 to axially align thecomponents and radially align/center them along the interface 1067. Theresulting components can be coupled to the swirl ring 150 to form afirst sub-assembly 1502. For example, the outer retaining feature 1056of the electrode insulator 754 can matingly engage the inner retainingfeature 1054 of the swirl ring 150 to axially align the components andradially align/center them along the interface 1055. In someembodiments, one or more o-rings are used to further secure thecomponents (e.g., the swirl ring 150, the electric insulator 75 and theelectrode 108) relative to each other in the first sub-assembly 1502. Asecond sub-assembly 1504 can be formed by affixing the nozzle 110 to thenozzle jacket 111, where the nozzle 110 can be disposed in the hollowbody of the nozzle jacket 111. In some embodiments, one or more o-ringsare used to further secure the nozzle 110 and the nozzle jacket 111relative to each other in the second sub-assembly 1504.

The first sub-assembly 1502, the second sub-assembly 1504, and theshield 114 can be directly attached to the cartridge frame 112 to formthe cartridge 104. For example, an outer retaining feature 1052 of theswirl ring 150 can matingly engage an inner retaining feature 1058 ofthe cartridge frame 112 to axially align the components and radiallyalign/center them along the interface 1053. An outer retaining feature1070 of the nozzle 110 can matingly engage another inner retainingfeature 1072 of the cartridge frame 112 to axially align the componentsand radially align/center them along the interface 1071. An outerretaining feature 1062 of the cartridge frame 112 can matingly engage aninner retaining feature 1064 of the shield 114 to axially align thecomponents and radially align/center them along the interface 1063. Inaddition, a distal end of the shield 114 can be crimped into anindentation 1065 on the outer surface of the cartridge frame 112 tofurther secure the two components together. In some embodiments, one ormore o-rings are used to assist in the engagement of the firstsub-assembly 1502, the second sub-assembly 1504, and/or the shield 114to the cartridge frame 112.

It should be understood that various aspects and embodiments of theinvention can be combined in various ways. Based on the teachings ofthis specification, a person of ordinary skill in the art can readilydetermine how to combine these various embodiments. Modifications mayalso occur to those skilled in the art upon reading the specification.

What is claimed is:
 1. A torch head for a liquid-cooled plasma arctorch, the torch head comprising: a torch body; and a torch insulatorhaving a substantially non-electrically-conductive insulator body, thetorch insulator coupled to the torch body, the torch insulatorincluding: a first liquid coolant channel, disposed within the insulatorbody, configured to conduct a fluid flow from the torch head into aconsumable cartridge along a first preexisting flow path; a first liquidreturn channel, disposed within the insulator body, configured to returnat least a portion of the fluid flow from the cartridge to the torchhead along the first preexisting flow path; and a gas channel, disposedwithin the insulator body, configured to conduct a first gas flow fromthe torch head to the cartridge along a second preexisting flow path,wherein the first and second preexisting flow paths are fluidly isolatedfrom each other, and wherein the first liquid coolant channel and thefirst liquid return channel are radially non-concentric about andradially offset in relation to a central longitudinal axis of theinsulator body.
 2. The torch head of claim 1, further comprising analignment feature configured to radially secure the torch head to thecartridge in a predetermined orientation to maintain the first andsecond preexisting flow paths extending through the torch insulator andthe cartridge.
 3. The torch head of claim 2, wherein the first liquidcoolant channel is configured to substantially align with acorresponding first liquid coolant channel of the cartridge when thetorch head is radially secured to the cartridge via the alignmentfeature.
 4. The torch head of claim 3, wherein the first liquid returnchannel is configured to substantially align with a corresponding firstliquid return channel of the cartridge when the torch head is radiallysecured to the cartridge via the alignment feature.
 5. The torch head ofclaim 4, wherein the first preexisting flow path comprises the firstliquid coolant channel of the torch head, the corresponding first liquidcoolant channel of the cartridge, the corresponding first liquid returnchannel of the cartridge and the first liquid return channel of thetorch head.
 6. The torch head of claim 1, wherein the torch insulatorfurther comprises a second gas channel, disposed within the insulatorbody, configured to conduct a second gas flow from the torch head to thecartridge along a third preexisting flow path, wherein the second andthird preexisting flow paths are fluidly isolated from each other. 7.The torch head of claim 1, wherein the gas channel is radiallynon-concentric with respect to the longitudinal axis extending throughthe insulator body.
 8. The torch head of claim 1, wherein the torchinsulator further comprises a central channel disposed in the insulatorbody, the central channel configured to provide at least one of (i) acurrent or (ii) at least a portion of the fluid flow from the torch headto the cartridge.
 9. The torch head of claim 1, wherein the torchinsulator further comprises an electrical channel disposed in theinsulator body, the electrical channel configured to receive an ohmiccontact connection that establishes an ohmic contact between the torchhead and the cartridge.
 10. The torch head of claim 1, wherein the torchinsulator further comprises: a current ring at a distal end of theinsulator body, the current ring configured to receive a pilot arccurrent from the cartridge; and a pilot arc channel configured toreceive a pilot arc connection that is in electrical communication withthe current ring to pass the pilot arc current from the cartridge to thetorch head.
 11. A torch head for a liquid-cooled plasma arc torch, thetorch head comprising: the torch head of claim 1; a cavity in theinsulator body; and a communication device comprising a circuit boardand a radio-frequency identification (RFID) antenna coil, the RFIDantenna coil electrically connected to the circuit board and positionedadjacent a distal end of the communication device; wherein thecommunication device is located in the cavity such that the RFID antennacoil is positioned at the distal end of the insulator body.
 12. Thetorch head of claim 11, wherein the communication device furthercomprises a sealed housing for preventing liquid from entering therein.13. The torch head of claim 11, wherein the circuit board of thecommunication device is configured to power the antenna coil and read anRFID signal received by the antenna coil.
 14. The torch head of claim11, wherein the communication device further comprises a connector at aproximal end of the communication device.
 15. The torch head of claim11, wherein the gas channel, the first liquid coolant channel, the firstliquid return channel and the cavity are radially non-concentric inrelation to the central longitudinal axis of the insulator body.
 16. Thetorch head of claim 11, wherein the antenna coil is positioned at an endface of the distal end of the communication device.
 17. A torch head fora liquid-cooled plasma arc torch, the torch head comprising: a torchbody; and a torch insulator having a substantiallynon-electrically-conductive insulator body, the torch insulator coupledto the torch body, the torch insulator including: a first liquid coolantchannel, disposed within the insulator body, configured to conduct afluid flow from the torch head into a consumable cartridge along a firstpreexisting flow path; a first liquid return channel, disposed withinthe insulator body, configured to return at least a portion of the fluidflow from the cartridge to the torch head along the first preexistingflow path; a gas channel, disposed within the insulator body, configuredto conduct a first gas flow from the torch head to the cartridge along asecond preexisting flow path, and a gas valve embedded in the insulatorbody, the gas valve in fluid communication with the gas channel, the gasvalve configured to select one of a plurality of gases for supply to thegas channel, wherein the first and second preexisting flow paths arefluidly isolated from each other and.
 18. A torch head for aliquid-cooled plasma arc torch, the torch head comprising: a torch body;and a torch insulator having a substantially non-electrically-conductiveinsulator body, the torch insulator coupled to the torch body, the torchinsulator including: a first liquid coolant channel, disposed within theinsulator body, configured to conduct a fluid flow from the torch headinto a consumable cartridge along a first preexisting flow path; a firstliquid return channel, disposed within the insulator body, configured toreturn at least a portion of the fluid flow from the cartridge to thetorch head along the first preexisting flow path; a gas channel,disposed within the insulator body, configured to conduct a first gasflow from the torch head to the cartridge along a second preexistingflow path, a second liquid coolant channel, disposed within theinsulator body, configured to conduct at least a portion of the fluidflow from the torch head into the cartridge along the first preexistingflow path; a second liquid return channel, disposed within the insulatorbody, configured to return at least a portion of the fluid flow from thecartridge to the torch head along the first preexisting flow path; and adistribution channel, disposed within the insulator body, connecting thefirst liquid return channel with the second liquid coolant channel,wherein the first and second preexisting flow paths are fluidly isolatedfrom each other.
 19. The torch head of claim 18, wherein the firstpreexisting flow path flows over a sequence of channels in the insulatorbody comprising the first liquid coolant channel, the first liquidreturn channel, the distribution channel the second liquid coolantchannel, and the second liquid return channel.
 20. A torch head for aliquid-cooled plasma arc torch, the torch head comprising: a torchinsulator having an insulator body that is electrically non-conductive;a first cooling channel and a third cooling channel, disposed in theinsulator body, each configured to conduct a first fluid flow from thetorch head into a cartridge; a second cooling channel and a fourthcooling channel, disposed in the insulator body, each configured toreturn at least a portion of the first fluid flow from the cartridge tothe torch head; and a first distribution channel, disposed in theinsulator body, connecting the second cooling channel and the thirdcooling channel, the first distribution channel configured to direct thefirst fluid flow from the second channel to the third channel.
 21. Thetorch head of claim 20, wherein the first distribution channel iscircumferentially oriented to connect the second cooling channel and thethird cooling channel.
 22. The torch head of claim 20, wherein thefirst, the second, the third and the fourth cooling channels arenon-concentric about a longitudinal axis extending through the insulatorbody.
 23. The torch head of claim 20, wherein each of the first, thesecond, the third and the fourth cooling channels are asymmetric withrespect to a central longitudinal axis extending through the insulatorbody.